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Overflow Skimmers

Contents:

  1. Over flow or skimmer box
    by frazier-at-maverick.hrl (Greg Frazier) (17 Jul 92)
  2. [M]Siphon Continued....
    by ahughes-at-arch386.hyperdesk.com (Arch Hughes) (23 Oct 92)
  3. [Q] prefilter siphon
    by resler-at-liberty.mas.vcu.edu (Dan Resler) (Tue, 30 Aug 1994)
  4. My trickle-filter design.
    by "David W. Webb" <dwebb-at-ti.com> (Fri, 24 Mar 95)
  5. My prefilter is LOUD
    by rbrown-at-bbn.com (Ralph Brown) (25 Feb 92)
  6. Silencing prefilter - Clarification
    by rbrown-at-bbn.com (Ralph Brown) (27 Feb 1992)
  7. Self Starting Syphons (How they work)
    by oleg-at-Veritas.COM (Oleg Kiselev) (17 Jan 92)
  8. DIY spill box for WD/sump?
    by raiar-at-vulcan.inlink.com (Gary V. Deutschmann Sr.) (19 Apr 1995)
  9. Update to my skimmer designs.
    by David Webb <DAWB.DSKPO33B-at-dsks62.itg.ti.com> (Tue, 19 Sep 95)
  10. Surface Scum
    by esarchy/wsunix.wsu.edu (Sun, 24 Aug 1997)
  11. Mucho Big tank - clean big tank - AGAIN2
    by jude/pconline.com (Nathanael Henderson) (1 Jan 1998)
  12. Mucho Big tank - clean big tank - AGAIN2
    by "Nestor10" <nestor10/mindspring.chkr.com> (Wed, 31 Dec 1997)
  13. Flow rates and bulkhead diameters?
    by ptimlin/lynx02.dac.neu.edu (patrick timlin) (17 Feb 1998)
  14. re: overflow
    by "David W. Webb" <dwebb/ti.com> (Mon, 26 Oct 1998)
  15. New Fish Room -Reply
    by Dave Gomberg <gomberg/wcf.com> (Mon, 02 Nov 1998)
  16. New Fish Room -Reply
    by IDMiamiBob/aol.com (Tue, 3 Nov 1998)
  17. Re:surface extractor
    by Sue Martin <wamart/vaxxine.com> (Sat, 16 Oct 1999)

Over flow or skimmer box

From: frazier-at-maverick.hrl (Greg Frazier)
Date: 17 Jul 92

zag25-at-isuvax.iastate.edu writes: 

: I was wondering if anyone out there has ever been sucessful in
building a skimmer box or overflow as some people call them.. I have
heard of people making there own and was wondering if anyone knows
how-- As you know a good one can be very expensive Ple ase respond if
you know ANYTHING about making one..

First of all, let me say that I am a big fan of carriage
returns.  It is one of my favorite keys on the keyboard,
and I strongly recommend that you find yours and learn
how to use it! :-) (<80 char lines are nice).  Second,
yes, I built an overflow once.  It was mostly for fun - I
stuck it on a 5g tank.  Anyway, as far as I can tell, they
are only practical if you have a sump.  Without a sump, the
water level in your tank varies, and you have to play games
like the people with the Eheim overflow boxes have been
talking about - ugly.  So, given that you have a sump,
what you want to do is glue a box to a corner of your aquarium,
so that when the water reaches the level you want it to be,
it will overflow into the box.  What I did at this point was
to take the "box" of an old external filter, drill a hole
through the bottom of it (actually, it already had a hole
where the impeller fit into it), and glued a standpipe to
it.  I then fashioned a U-pipe that went from inside the
overflow box to inside the external filter box.  The ends
of the U-pipe were below both the edges of the overflow
box and below the top of the standpipe, and the top of
the standpipe was below the edges of the overflow box.
So, you have the aquarium full of water up to the level
of the inside box, and you have a sump full of water.  As
you pump water from the sump into the tank, it overflows
into your overflow box.  The U-pipe (which had been previously
primed) syphons water out of your tank into the external
filter box.  Water passes through whatever filtration material
you have put into the external filter box and goes down the
standpipe.  When you turn the pump off, water will drain out
of the inside box only to the level of the standpipe, leaving
both ends of the U-pipe in the water so you don't lose your
syphon.  If you have a plexi tank, you can drill a hole through
the side of the tank, instead of using a U-pipe, and then you
don't have to worry about a syphon or a standpipe.  Picture
below...


  ~ is H2O level
  I is tank wall
  | is overflow box wall
  1 is external box wall
  # is pipe
                     #######
                     #  I1 #    1
~~~~~~~~~~~~~~~~~~|  # |I1 #    1
                  |~~#~|I1~#~~#~1
                  |  # |I1 #  # 1
   ><(>           ------I-----#--
      %gt;<(>              I     #  <- water drains down standpipe and back
                        I               to sump


Addendum 1: if you use a powerhad to pump water from sump to
        tank, or if you use one for current w/in your tank,
        apparently you can run an airline from the peak of
        the U-pipe to the venturi intake of the powerhead to
        prevent air from accumulating in the U-pipe (and perhaps
        even to start the syphon when it is completely un-done).

Addendum 2: the U-pipe must have a large diameter to be able
        to drain water as quickly as you are pumping it into
        the tank (assuming you want a significant water flow).
--


Greg Frazier    frazier-at-CS.UCLA.EDU     !{ucbvax,rutgers}!ucla-cs!frazier

[M]Siphon Continued....

by ahughes-at-arch386.hyperdesk.com (Arch Hughes)
Date: 23 Oct 92

I tried to mail this, but can't get to Ross' host.

  Why do you need two siphons?  Doesn't the box on the outside have a
  "drilled" exit in the side for the water rather than taking it over
  the top?


            -------------------- Siphon Tube
            |                  |
            |  --------------  |
            |  |            |  |
    Over-   |  |  |  ||   | |  |   |
    flow    |  |  |  ||   | |  |   |
            |  |  |  ||   | |  |   |
  Max    |  |  |  |  ||   | |  |   |
  Level  |  |  |  |  ||   | |  |   |
         |  |  |  |  ||   | |  |   ------- Max Water Level
         |  |  |  |  ||   | |  |         |
         |  |  |  |  ||   | |  |   ----- | Min Water Level
         |  |  |  |  ||   | |  |   |   | |
  Min    |  |  |  |  ||   | |  |   |   | |
  Level  |        |  ||   | |  |   |   | |
         |        |  ||   |        |   | |
         |        |  ||   |        |     Down to
         |        |  ||   |        |     Wet/Dry
         |        |  ||   |        |
         |        |  ||   |        |
         |        |  ||   |        |
         ---------   ||   ----------
                     ||
                     ||     Outside
       Inside        ||       Box
        Box          ||
                     ||
                Tank ||
                Wall



  Of course, in my diagram, if the return stops the inside box will drop
  to the level of the siphon, and the siphon will break.  Thus, the
  inside box must have two siphons and the box either be "two boxes" or
  be a two chamber box.  Right?


In article <1992Oct22.004611.11723-at-unislc.uucp>, livings-at-unislc.uucp (Ross
Livingston) writes:

[...]

> that this would never do.  I ended up making my own.  This gave me the
choice
> of it's exact dimensions.  A local plastics place sold me the acrylic and
cut
> all the pieces to size for no extra cost.  By the time I was done, I was
into
> it just over $20.  It's a breeze to assemble.  I used two 1" siphons to be
> certain my flow would be more than my pump, and for the second to serve as
> protection in the advent that one of the siphons be broken.  Mine has been
> running for over a month now.  

[...]
> 
> Good Luck
> 
> -- 
> Ross Livingston, Unisys Corp.  |  Phone   (801) 594-6217
> 322 North  2200 West,   D1V03  |  Fax     801-594-4861 / 801-594-6708
> Salt Lake City, UT   84116     |  E-Mail  livings-at-unislc.slc.unisys.com

[Q] prefilter siphon

by resler-at-liberty.mas.vcu.edu (Dan Resler)
Date: Tue, 30 Aug 1994
Newsgroup: rec.aquaria

jselling-at-tc1009.pto.ford.com (Joseph S. Sellinger) writes:

>With all due respect, how bout this one... Drill a hole in the top of the 
>u tube and glue an air line into the hole. Then install a check valve on the 
>air line. Now whenever air gets into the u tube all you need to do is suck.
>You could also just silicone the check valve to the u tube. 

>Another thing you could do is take the air line straight to a venturi on a
>power head. This would solve the power down problem and I'll bet make you
>feel a little safer. 

>What do ya think? 

This stuff probably should go in the FAQ as it sees like it gets
discussed every few weeks. Your solution will work of course and is
a more permanent version of what I suggested. You don't need to
connect the air line to the venturi on a PH, though. Just stick it in
the intake for any water pump and it'll work.

dan
--
Dan Resler                              email: resler-at-liberty.mas.vcu.edu
Dept. of Mathematical Sciences            
Virginia Commonwealth University           
Richmond, VA  23284-2014 USA


My trickle-filter design.

by "David W. Webb" <dwebb-at-ti.com>
Date: Fri, 24 Mar 95

"Smart" siphon trickle filter.  
Designed by David W. Webb
dwebb-at-ti.com

The smart siphon controls the water level of 
the tank both when the pump is running and when 
it is off (like after a lightning strike, or
when you're doing maintenance).  It is ready to 
go when the pump starts again because it never 
loses the siphon.

I designed this siphon after looking at the 
trickle filter drains that were on the market
and deciding that they were too difficult
to hide.  This tank drain is intended for
non-drilled tanks, and tanks that can't be
drilled safely.

I've been using this system for several years
with only minor changes to the design.  It cost
me about $65 to implement (without the heaters
and pump).  I think I could do it now for half
that amount.

Blanket Disclaimer:
I am not responsible for any damage to personal 
property or injury to persons if you use of any 
of my suggestions or designs.  I reserve the 
right to modify my designs at any time.

     __                   C._________________D.
    //\\                   |  _____________  |
   || =\\==================| |===          | |
   || # N.                 | |  #          | |
   || #~~~~~~~~~|   |~~~~~~| |~~#    G.| | | | 
   || #       A.|   |      | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #  ____| | | |
   || #          |~|       | |  # |  __ ~| | |
   || #          | |_______| |  # | |F.| | | |   
   || #        B.|___________|  # | |  | | | |
   || ########################### | |  | | | |
   ||                             | |  | | | |
    \\________                    | |  | | | |
     \________\M.       __________| |  | | | |
              \\     H.|  __________|  | | | |
            ===||======| |=====        | | | |
            #  ||  |   I.     #        | | | |
            #  ||  |   J.     #        | | | |
            #  ||  |          #        | | | |E.
            # _||_ |----------#        | | | |
            #~|L.|~|~~~~~~~~~~#        | |_| |
            # |  | |   K.     #        |_____|
            ###################  

A.  The tank drain: This controls your water
    level and also skims the scum off of the 
    top of your tank.  The top of the A. tube
    should be about .25" below your desired
    water level.  A bit of advanced planning 
    will let you hide both riser tubes behind
    tall objects in your tank.
    The tank drain will quickly remove all 
    floating objects that are not anchored 
    down (including flake food).  This tank
    drain is shown with a widened mouth.  
    place a plastic screen in the bottom of 
    the mouth and add pre-filter media on top
    of it.  You can also opt to let everything
    pass through and just pre-filter it at the
    drip plate if you don't plan to use a
    sprayer bar.
    I prefer to place the tank drain 
    components out of sight.  You can do 
    this by positioning the vertical tubing
    behind tall vertical objects and by 
    covering the horizontal portion of the
    J-tube (B.) with gravel.

B.  The J-tube should be as low as possible 
    in your tank.  A good place to put it is 
    under the gravel at the back of the tank.
    The J-tube must be below the bottom of
    the waterfall (F.) I reccommend 2-3" of 
    vertical separation for optimum siphon
    stability under high flow conditions.

C.  The siphon draws water out of the tank
    and into the velocity loop (E.)  

D.  An air fitting on the outside elbow of
    the siphon provides an easy way to start
    the siphon.
    Joseph S. Sellinger suggests that you
    connect this fitting to the air venturii
    on one of your power heads.  I believe 
    that this will work admirably.  
    Alternatively, you may want to consider
    using two drains for redundancy in case
    the siphon on one develops a leak or 
    sucks down some air bubbles.

E.  The velocity loop should drop as far down
    as is practical (3-4').  This loop helps 
    stabilize the siphon at high drain rates.
    The velocity loop also holds the water 
    necessary to start or re-start the siphon. 

F.  The waterfall drains the siphoned water 
    into the sump.  The waterfall must be 
    positioned above the J-tube (B.) or the 
    siphon will fail when the pump is off.

G.  The surge tube allows you to fill the 
    velocity loop to start the siphon.  It
    also acts to buffer water surges.  The
    top of the surge tube should be even with 
    or above the top of the tank drain (A.)
    to prevent spilling any water during a 
    surge.  (Surges occur when you add water
    to the tank rapidly.)

H.  The drain into the sump.  

I.  Spray bar.  You can use an all-plastic
    garden sprinkler or sprinkler-system head
    for this.  I actually use a trickle plate
    on my system at home.  Trickle plates are
    better for plant tanks because they don't
    release quite as much CO2 into the air.

J.  Bio-filtration media.  I use a 2 gallon 
    plastic hexagonal tank with holes drilled
    in the bottom and in the lid.  Caution: 
    the lid is a bit brittle and might crack
    if allowed to hop when the drill bit 
    finishes the hole.  I filled the tank 
    with bio-balls, but would have used shredded
    clear soda straws if I had heard about them
    before I started ($$$$).  The soft plastic
    rim of the tank lifts off.  After filling
    it with media, I removed the rim,  placed
    the lid on top of the media, and then 
    replaced the rim.  I put a blue-white filter
    pad on top of the upper plate and dump the 
    output of my drain onto the media.  The 
    hex-tank rests on a stand that I constructed
    from PVC tubing.

K.  Heaters.  This is a good place to put 
    your heaters.  Obviously, you can place 
    them anywhere.  Redundant heaters are
    reccommended.

L.  Water Pump.

M.  Return line to the tank.

N.  Diffuser(s).  You should bore a hole in 
    the return line just above the water 
    level (inside the tank).  This hole 
    prevents water from siphoning back into
    the sump through the return line when the
    pump is off. 
    For plant tanks with CO2 injection, you 
    might want to look into a diffuser system
    with heads that stick up from the gravel
    and direct water in a circular pattern 
    around your tank.  You can easily build 
    one of these out of PVC.  CO2 injected
    or not, plant tanks should have as little
    surface agitation as possible.  CO2 
    evaporates very easily without any 
    mechanical help.

As water evaporates, the water level will 
change in your sump, NOT your tank.  Check 
the water level in your sump regularly to 
prevent damage to your pump and heaters.

With this design you can conserve water by 
vaccuuming your substrate directly into 
a net suspended above the sump.
 
I also have another drain of this design 
in the sump to drain excess water out
during a water change.

-- 
---------------------------------------------------------
David W. Webb      
dwebb-at-ti.com

Any correlation between my opinions and those of Texas 
Instruments is purely coincidental.  (I don't speak for
TI)
---------------------------------------------------------



My prefilter is LOUD

by rbrown-at-bbn.com (Ralph Brown)
Date: 25 Feb 92
Newsgroup: rec.aquaria

I had the same problem and have solved it as follows:

First, the problem - if the water level is low enough that air can be sucked
down into the pipe, it gets noisy, I suspect mainly because of the air 
allowing sound to bounce around inside the pipe with the 
energy of the air bubbling back up in the water driving it.

A solution follows from this that if you can keep the water level above where 
air is sucked down, the noise stops.

I did this by building an inverted U tube much like a sink trap. The water
must flow up over the top of the inverted U to get down to the filter. The top
of the U should be below the level of the skimmer so it all self starts.
If you have soft hose, you could try just bending it up to get the high point
about 3" above the bottom of the prefilter bottom. The idea is to force
the water level up above the level were it can draw in air.
  
In my tank, this didn't work directly because a strong siphon developed which
still pulled the level in the box down low enough to suck in air. 
I cured that by a small hole at the top of the inverted U to break the siphon.
This still emitted a sound (much less) which I've pretty much eliminated with a
piece of air line stuck into the hole and lead into the basement. I suspect
putting the end into a cloth filled box or something would also work.

I built the inverted U out of PVC with a hose connection to go back to
clear tubing and would recommend it over the bend soft tubing since it
eliminates kinking. The PVC is easy to drill and work with also.

Ralph


Silencing prefilter - Clarification

by rbrown-at-bbn.com (Ralph Brown)
Date: 27 Feb 1992
Newsgroup: rec.aquaria

It has been pointed out to me that my earlier explanation may not have
been completely lucid. The following diagram should help. The basic idea
is the same as a sink trap.                                                           
                                                            
                                                            
                  Contrivance to silence prefilter        
                                                            
       Vacuum                                               
       Breaker  (a piece of airline)                        
         |                                                  
         V         Inverted U Tube                          
        | |                                  |   Prefilter
      +-| |---------------+                  |             
      |=== Water Level ===|                  |              
      |    +---------+    |                  |==== Prefilter Water ====
      |    |         |    |                  |              
      |    |         |    |                  |              
      |    |         |    |                  |              
      |    |         |    |                  |              
      |    |         |    | <- PVC Pipe      |             
      |    |         |    |                  |              
      |    |         |    |                  |              
      |    |         |    |                  |              
      |    |         |    |                  |              
      |    |         |    |                  |              
                     |    |                  +-----+    +-------
       to            |    |                        |    |   Prefilter
      filter         |    +------------------------+    |   Outlet
                     |                                  |   
                     +----------------------------------+   
                                                            
                                                            

This works because water in the prefilter is kept well above the
outlet, so no air can be drawn in. In my tank it's about 6.5" 
deep. The vacuum breaker ensures that the water doesn't syphon
but may be a bit noisy itself. Putting a piece of airline in it
and leading it into the cabinet, basement, etc will eliminate that
noise also. 

Because the water level is so high, the noise of water falling into the
skimmer and over the divide in the prefilter is also eliminated.  An
additional benefit is that any filter material in the prefilter box is
completely covered so it's all in use.


Self Starting Syphons (How they work)

by oleg-at-Veritas.COM (Oleg Kiselev)
Date: 17 Jan 92
Newsgroup: rec.aquaria

gl-at-minnow.sp.unisys.com (Gene Lee) writes:
>The following diagram represents what I understand to be a self starting
>syphon.  Can anybody describe the dynamics of its operation.  I have included
>a diagram for you to reference.

Your diagram is different from what I understand to be a self-starting
(or rather self-REstarting) syphon.  The one I am familiar with is built 
around the standpipe principle:

Normal conditions:
		+------------+
		|            |
		|  +------+  |            
                |  ||     |  |           |
~~~~~~~~~~~~~~~~|  ||     |  |~~~~~~~~~~~|
            |   |  ||     |  |   | $$$$$ |
	    |   |  ||     |  |   | $$$$$ | <- prefilter
 tank       |      ||     |      | $$$$$ |
	    +------+|     +---------+ +--+
		    |               | |  <--- to filteR
					

On power off, the water continues to drain into the filter until the water 
level drops enough to stop the siphon.  This kind of design also serves to 
keep from getting the whole tankfull of water dumped on the floor:

		+------------+
		|            |
		|  +------+  |            
                |  ||     |  |           |
                |  ||     |  |           |
~~~~~~~~~~~~|~~~|  ||     |  |~~~| $$$$$ |
            |   |  ||     |  |   | $$$$$ | <- prefilter
 tank       |      ||     |      | $$$$$ |
	    +------+|     +---------+ +--+
		    |               | |  <--- to filter

Note that as the water level has dropped, the "pockets" on each end of the 
siphon are still full of water and that keeps the siphon filled as well.  
The water is now resting in the sump.

Once the pump is restarted and the water level in the tank starts rising
and the water again starts running through the siphon.

One rather interesting modification is to drill a hole at the top of
the siphon with an air tubing sealed into the hole and attached on the 
other end to a venturi mechanism elsewhere in the system.  Adjusting the 
suction to be minimal it is possible to remove the inevitable air bubbles
which accumulate at the apex of the siphon and eventually can cause the 
siphon to collapse.  A particular implementation I have seen described 
in the literature was in George Meravi's article in one of last year's issues
of the Journal of the AKA.
-- 
"and a letter in your writing doesn't mean you're not dead" -- Pixies.

Oleg Kiselev                                             oleg-at-veritas.com
VERITAS Software                           ...!{apple|uunet}!veritas!oleg


DIY spill box for WD/sump?

by raiar-at-vulcan.inlink.com (Gary V. Deutschmann Sr.)
Date: 19 Apr 1995
Newsgroup: alt.aquaria

The only thing I can add to the previous post is to use smaller syphon tubes,
for most systems, 2" would be way to big and constantly catch air from the
water and lose its prime.  I even had trouble with 1" syphons losing their
prime, once I switched to 3/4 inch tubes I never had any trouble since then.

For what its worth, I started using flat square or rectangular tubing.  Like
a trim piece from a piece of exolite, being clear I could see if air was
collecting and being flat, seemed to force what little air separated from
the water was forced through.

On my large tank, I am using three separate 3/4 inch syphon tubes, all in the
same box, when I tried using the 1 inch tubes I started having troubles 
again.  So I switched back to the smaller diameter tubes.

Gary



Update to my skimmer designs.

by David Webb <DAWB.DSKPO33B-at-dsks62.itg.ti.com>
Date: Tue, 19 Sep 95

If/when you're interested or get around to it, this is the updated version of 
my tank drain/skimmer designs.

============================================================================
"Smart" siphon trickle filter.  
Designed by David W. Webb
dwebb-at-ti.com

The smart siphon controls the water level of the tank both when the pump is 
running and when it is off (like after a lightning strike, or when you're doing
maintenance).  It is ready to go when the pump starts again because it never 
loses the siphon.

I designed this siphon after looking at the trickle filter drains that were on
the market and deciding that they were too difficult to hide.  This tank drain
is intended for non-drilled tanks, and tanks that can't be drilled safely.

I've been using this system for several years with only minor changes to the 
design.  It cost me about $65 to implement (without the heaters and pump).  I 
think I could do it now for half that amount.

Blanket Disclaimer:
I am not responsible for any damage to personal property or injury to persons 
if you use any of my suggestions or designs.  I reserve the right to modify my 
designs at any time.

     __                   C.-----------------D.
    //\\                   |  -------------  |
   || =\\==================| |===          | |
   || # N.                 | |  #          | |
   || #~~~~~~~~~|   |~~~~~~| |~~#    G.| | | | 
   || #       A.|   |      | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #      | | | |
   || #          | |       | |  #  ----  | | |
   || #          |~|       | |  # |  -- ~| | |
   || #          |  -------  |  # | |F.| | | |   
   || #        B. -----------   # | |  | | | |
   || ########################### | |  | | | |
   ||                             | |  | | | |
    \\________                    | |  | | | |
     \________\M.       ----------  |  | | | |
              \\     H.|  ----------   | | | |
            ===||======| |=====        | | | |
            #  ||  |   I.     #        | | | |
            #  ||  |   J.     #        | | | |
            #  ||  |          #        | | | |E.
            # _||_ |----------#        | | | |
            #~|L.|~|~~~~~~~~~~#        | | | |
            # |  | |   K.     #        |  -  |
            ###################         -----

A.  The tank drain: This controls your water level and also skims the scum off
    of the top of your tank.  The top of the A. tube should be about .25" below
    your desired water level.  A bit of advanced planning will let you hide 
    both riser tubes behind tall objects in your tank.
    The tank drain will quickly remove all floating objects that are not 
    anchored down (including flake food).  
    This tank drain is shown with a widened mouth.  Place a plastic screen in 
    the bottom of the mouth and add pre-filter media on top of it.  You can 
    also opt to let everything pass through and just pre-filter it at the drip 
    plate if you don't plan to use a sprayer bar.
    Note: you may need to experiment with putting pre-filter media in the tank 
    drain.  A large drain might be unsightly, and a small drain may require 
    frequent filter media cleaning     to prevent clogs.
    I prefer to place the tank drain components out of sight.  You can do this 
    by positioning the vertical tubing behind tall vertical objects and by 
    covering the horizontal portion of the J-tube (B.) with gravel.
    After I put the pre-filter in the overflow, I have now gone back to a 
    simple tube to the top of the tank.  I plan to implement a settling tank 
    design of mine to capture debris and wayward fish before the pre-filter.


B.  The J-tube should be as low as possible in your tank.  A good place to put 
    it is under the gravel at the back of the tank.  The J-tube must be below 
    the bottom of the waterfall (F.) I reccommend 2-3" of vertical separation 
    for optimum siphon stability under high flow conditions.

C.  The siphon draws water out of the tank and into the velocity loop (E.)  

D.  An air fitting on the outside elbow of the siphon provides an easy way to 
    start the siphon.
    Joseph S. Sellinger suggests that you connect this fitting to the air 
    venturii on one of your power heads.  I believe that this will work 
    admirably.  However, you will need to either place the powerhead in the 
    sump, or make sure it is high up in the tank because water will siphon out
    of it into the sump too.
    Alternatively, you may want to consider using two drains for redundancy in
    case the siphon on one develops a leak or sucks down some air bubbles.

E.  The velocity loop should drop as far down as is practical (3-4').  This 
    loop helps stabilize the siphon at high drain rates. The velocity loop 
    also holds the water necessary to start or re-start the siphon. 

F.  The waterfall drains the siphoned water into the sump.  The waterfall must 
    be positioned above the J-tube (B.) or the siphon will fail when the pump 
    is off.

G.  The surge tube allows you to fill the velocity loop to start the siphon.  
    It also acts to buffer water surges.  The top of the surge tube should be 
    even with or above the top of the tank drain (A.) to prevent spilling any 
    water during a surge.  (Surges occur when you add water to the tank 
    rapidly.)  You can place a cap with a hole drilled in it on top of the
    surge tube to act as a muffler.  This will effectively limit the amount
    of noise that comes from this part of the system.  I recommend that you 
    do not cement the cap in place, since you might need to remove it later
    to re-start the siphon if you have to tear the system down at some point.

H.  The drain into the sump.  

I.  Spray bar.  You can use an all-plastic garden sprinkler or sprinkler-
    system head for this.  I actually use a trickle plate on my system at home.
    Trickle plates are better for plant tanks because they don't release quite 
    as much CO2 into the air.

J.  Bio-filtration media.  I use a 2 gallon plastic hexagonal tank with holes 
    drilled in the bottom and in the lid.  Caution: the lid is a bit brittle 
    and might crack if allowed to hop when the drill bit finishes the hole.  
    I filled the tank with bio-balls, but would have used shredded clear soda 
    straws if I had heard about them before I started ($$$$).  The soft plastic
    rim of the tank lifts off.  After filling it with media, I removed the rim,
    placed the lid on top of the media, and then replaced the rim.  I put a 
    blue-white filter pad on top of the upper plate and dump the output of my 
    drain onto the media.  The hex-tank rests on a stand that I constructed
    from PVC tubing.  

K.  Heaters.  This is a good place to put your heaters.  Obviously, you can 
    place them anywhere.  Redundant heaters are reccommended.

L.  Water Pump.

M.  Return line to the tank.

N.  Diffuser(s).  You should bore a hole in the return line just above the 
    water level (inside the tank).  This hole prevents water from siphoning 
    back into the sump through the return line when the pump is off. 
    For plant tanks with CO2 injection, you might want to look into a diffuser
    system with heads that stick up from the gravel and direct water in a 
    circular pattern around your tank.  You can easily build one of these out 
    of PVC.  CO2 injected or not, plant tanks should have as little surface 
    agitation as possible.  CO2 evaporates very easily without any mechanical 
    help.

If you get air bubbles in the siphon, you are either running too much water
through the system or too little.  There is what I call a "dead" spot for most
configurations of this design where raising the waterfall won't keep air 
bubbles from getting down the J-tube and into the siphon, but then they get
stuck there because the flow isn't fast enough to get them into the velocity
loop.  My solution to this problem is to either lower the flow or to raise it.
If your return lines from the pump get gooed up after a few years, you can
also run into this problem because of the reduced flow.

I recommend placing quick-disconnects at strategic places in this system so you
can easily tear it down for maintenance, modification, or repair.  

As water evaporates, the water level will change in your sump, NOT your tank.
Check the water level in your sump regularly to prevent damage to your pump and
heaters.

With this design you can conserve water by vaccuuming your substrate directly 
into a net suspended above the sump.  
 
I also have another drain of this design in the sump to drain excess water out
during a water change.                                                       
============================================================================

David W. Webb
Enterprise Computing Provisioning
Texas Instruments Inc. Dallas, TX USA
(214) 575-3443 (voice)  MSGID:       DAWB
(214) 575-4853 (fax)    Internet:    dwebb-at-ti.com
(214) 581-2380 (pager)  Text Pager:  pgr-at-msg.ti.com Subj:PAGE:David Webb

Surface Scum

by esarchy/wsunix.wsu.edu
Date: Sun, 24 Aug 1997

        Frank (and others),
        I can not say for sure what is causing the scum, but I have
battled this problem in the past. It is easy to take care of though.
        Purchase a piece of PVC pipe an inch or two longer than the length
of the intake pipe on your filter. Place a cap on one end of the pipe.
Attach two suction cups to the pipe so it will stick to the back of the
tank. 
        Now attach the pipe to the tank and feed the filter's intake pipe
into the PVC pipe. Place the top (open end) of the pipe about one half
inch (1.25cm) below the water's surface. Now the intake will draw water
from the surface like a skimmer. The scum will be collected in the filter.
                
                Filter intake
                ________[ ]_________ Water Level
                        [ ]
                      { [ ] }
                      { [ ] }
                      { [ ] } PVC Pipe
                      { [ ] }
                      { [ ] }
                      { [ ] }
                      {     }
                      _______ End Cap

        If the tank has a black background and you use black PVC it is
nearly invisible. A similar PVC tube can also be set up to hide heaters
and other equipment. These covers work well for catfish that burn
themselves on the heater and large aggressive fishes that like to break
heaters and/ or filter intakes. I hope this helps,
                                -Shane

I decided to stop drinking with creeps.
I decided to drink only with friends.
I've lost 30 pounds.
                - Ernest Hemingway


Mucho Big tank - clean big tank - AGAIN2

by jude/pconline.com (Nathanael Henderson)
Date: 1 Jan 1998
Newsgroup: rec.aquaria.freshwater.cichlids

: rec.aquaria.tech?)  Is a siphon, rather than a drilled tank, a
: feasible method of getting water into the sump?  I've thought of using

   One of the big problems with syphons on sumps is that they can lose
their syphon if the power fails--here's a better design a person on the
Discus-L mailing list gave me:


     |  | <-- syphon from tank.
     |  |
   | |  |       |   <-- overflow box outside of tank.
   |.|  |...  ..|   <-- water level.
   | |  |  |  | |
   | |  |  |  | |
   |_______|  |_|
           |  |
           |  |   <--tube to sump.

    By using a setup like this the system becomes a lot more reliable.  If
power fails, water will drain into the sump until the water level in the
tank falls below the top of the skimmer box, then stop.  With the above
outside overflow box design, water will stop flowing out of the overflow
box before the syphon can run dry, so when the power comes back on the
syphon system starts running again without a hitch.   This system also
lets you use very large tubing, since there would no longer be a problem
of the syphon pulling more water into the sump than the pump can handle.
Of course, all this requires you to either spend a lot of money on parts,
or build your own overflow boxes.  If you are worried about it, you could
build in some sort of overflow capability for the prefilter (where if the
water level rises high enough the flow would bypass the pre-filter.)  A
prefilter doesn't actually have to be part of the overflow boxes--you
could put it in-line just before or on top of the sump (which would also
let you get away with only one larger filter to maintain instead of
multiple smaller ones.)


Nathan H.


Mucho Big tank - clean big tank - AGAIN2

by "Nestor10" <nestor10/mindspring.chkr.com>
Date: Wed, 31 Dec 1997
Newsgroup: rec.aquaria.freshwater.cichlids

> Is a siphon, rather than a drilled tank, a feasible method of getting
water into the sump?

I see quite a few posts cropping up concerning overflowing sumps, or having the siphon out-pace the pumps, yadda, yadda...

There is a type of siphon that will only drain as much water as is added to the tank. It's called a self-levelling siphon. It is formed by double-looping the siphon and placing a hole at the top of the second loop. Water will only flow from the tank through the siphon until it reaches the level of the hole. Any time the tank level rises above the hole, the water will re-seek the level of the air "brake".

Since this may be hard to visualize, I have attached a small .gif file as an aid. I know it's a binary, but it serves a usefull purpose, and only eats less than 5K.

-Y-

nestor10-at-mindspring.com
".chkr" is for mail-bots


Flow rates and bulkhead diameters?

by ptimlin/lynx02.dac.neu.edu (patrick timlin)
Date: 17 Feb 1998
Newsgroup: rec.aquaria.marine.reefs,rec.aquaria.tech

R.S.Hashoian (hashoian-at-medadv.com) wrote:
: I'm in the process of drilling a tank to install a bulkhead to act as my
: overflow (left side upper corner).  This is being done on a 125 gallon
: tank and I want at least a 6x flow rate through the sump.

: What size i.d. hole should be drilled to allow ~ 750 to 800 gph?  Is
: there any list that shows diameter v.s. flow rate?  Is one big hole
: better than a couple smaller holes?

I have this cool little pocket reference book, called Pocket Ref (wow,
that's unique) put out by Abbeon Cal, inc. that has all kinds of cool
tables and reference material. In the water section it has tables for
friction loss in various pipes (copper vs PVC vs concrete etc), friction
losses for a given pipe type at some flow rate and given pipe diameter,
and also friction losses in pipe fittings like 90 degree elbows, T
fittings, 45 degree bends, etc.  Cool stuff.

I ordered the book directly from them.  1-800-922-0977.  $14.95 shipped.
See http://wwwa.com/abbeon for details.  Standard disclaimer: just a sat.
cust, no connection to company.  BTW, the ISBN is 1-885071-00-0 in case
Amazon or some such carries it for cheaper.

Let me know if I can look up something specific for ya.

Patrick Timlin         http://www.geocities.com/CapeCanaveral/4742/
ptimlin-at-geocities.com


re: overflow

by "David W. Webb" <dwebb/ti.com>
Date: Mon, 26 Oct 1998
To: Shane Olson <skolson/ptw.com>

>  Original text: 
>  From: Shane Olson <skolson@ptw.com>, on 10/23/98 10:56 PM:
>  To: dwebb@ti.com
>  
>  hi david,
>      I just read a post by you, i like the Idea of the overflow. what
>  size of tubing is used, and what kind I would realy like to try it
>  thanks alot

I haven't implemented this design, but it's basically the same mechanically
as the one you saw on the Krib.  It gives you advantages over the Krib
version though.  First, you have less tubing to look at.  Second, you can
remove the siphon portion for easy adjustment and servicing without
disturbing anything else.  Third, you can add an additional siphon without
having to add an additional bucket (you don't have to change the appearance
of your tank).

Here's a diagram of what is inside the tank.  The loop, waterfall, and
everything else stays the same, although if you want, you can be ingenious
in the way you implement these as well if you want to try and reduce the
amount of visible plumbing.  I'll give some examples.  In this diagram, the
bucket is set away from the side of the tank, creating a place things can
get stuck in.  I would jam the bucket into the corner or place it far
enough away from the corner that you don't run into this problem.


                /---------\   
                | /-----\ |    
                | |  :  | |                                      :
           |    | || :~|| |  |~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~:
           || |~| || : || |~~|                                   :
           || | | || : || |  |                                   :
           || | | || : || |  |                                   :
           || \-/ || : || |  |                                   :
           | -----/| : || |  |                                   :
            \     /  : |-----|                                   :
             \   /   =============================================
              | |           


This design adds another simplification at the waterfall that should enable
you to reduce noise (if you fiddle with things enough).

Inside the tank, you have your PVC bucket with the siphon going straight
down to just above the bottom.  This bucket is a large diameter section of
PVC, capped at one end.  If you need to, you can go with less than 3" or
4", but I think the larger sizes are safer.  For a large pump, you'll
probably want to use 1" tubing for the siphon and waterfall.  For a smaller
pump, you should be able to get away with 3/4" tubing.  I've only used 1/2"
tubing, but I now feel that 1/2" is too small for long-term siphon
stability.  Remember that the air fitting to draw the siphon must be on the
elbow outside the tank, not the one inside.

Here, the waterfall is inside a catch-tube and just dumps into the catch
tube.  The catch tube must be secured in some way so it doesn't fall over
(such as hanging it from the back of the tank), and you may decide that
this is too much trouble to do, but it works on the same concept as the
waterfall in my older designs, just with fewer visible pipes.  The catch
tube directs the water into your trickle tower or empty sump, depending on
which type of tank you're setting up.

--
David W. Webb           Texas Instruments
(972) 575-3443 (voice)  http://www.dallas.net/~dwebb
(214) 581-2380 (pager)  2145812380@alphapage.airtouch.com


New Fish Room -Reply

by Dave Gomberg <gomberg/wcf.com>
Date: Mon, 02 Nov 1998
To: apisto/majordomo.pobox.com

At 04:44 PM 11/2/98 -0500, you wrote:
>I have never heard of self regulating siphons.  What can you tell me about
them?

A self-regulating syphon is s-shaped and on the order of 8-10" wide when
looked at as an S.  

It is used with the parallel parts vertical, and only one part in the tank.
 So it starts at or near the bottom of the tank, rises to up over the top
of the tank, descends to somewhere near where it started, then turns upward
again.  The last upward leg should be adjustable height (like a piece of
tygon tubing at the end, for example).  If the syphon is filled with water
it will regulate the tank water level at the height of the the end of the
last outside (ascending) part.  If the water gets higher than this,
syphoning will start.   When the water level has declined to the height of
the outside part, the syphoning stops.   If the water level in the tank
drops dramatically as long as it remains above the bottom of the outside
part, the syphon will be maintained and will restart itself when the water
level again exceeds the height of the outside end.

The only fly in the ointment is that like most syphons, it can acquire an
air bubble and lose efficiency.  But that is a once-a-week maintenance
item, not daily like a level regulator.


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New Fish Room -Reply

by IDMiamiBob/aol.com
Date: Tue, 3 Nov 1998
To: apisto/majordomo.pobox.com

Kathy writes:

> The two biggest problems with implementing a system like this are
>getting 
>all the tanks drilled and what to do with the water coming out of the
>tanks.

No, No, No.  Don't drill the tanks.  That reduces their usefulness in the next
iteration of your fishroom  Set up a siphon of PVC pipes and elbows.  It can
drain over the back to a plastic peanut  butter jar, a plexiglass "triangular
catch pan" glued to the back/side of the tank, or anything else that you can
attach a drain to at the desired height.  A piece of sponge on the mouth of
the PVC in the tank will keep fish from getting across the barrier.

To attach the regulating drian, mark the location on the "receiving tank" (eg:
the peanut butter jar) where you want the water line on the tank to be
controlled at.  Then you drill a hole, glue in a little piece of stiff
tube/pipe, then stick some hose to the tube and run it to a rain gutter, which
can be set up to collect all the runoff at a central location for disposal.
You can also put the RO water storage tank above the tanks in the room, run
PVC over the tanks, stick brass air valves in where you need them, and set
them to drip at the desired rate into the tank.  Then you get a continuous
water change system as automatic as your RO unit or other storage tank filling
system.  Count the number of drops in a given volume, like a ml or Tbs, add
that up to figure out how many drops per litre/gallon, then set the desired
drip rate for each valve by counting and timing.  Then just check the drip
rate once in a while.  Flow rate in equals flow out + evaporation, and ther
you are.  Forget the pooter, it is more high tech than needed.

Bob Dixon


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Re:surface extractor

by Sue Martin <wamart/vaxxine.com>
Date: Sat, 16 Oct 1999

>Date: Sat, 16 Oct 1999 06:53:29 +0800
>From: Alfred Heng <alheng@pacific.net.sg>
>Subject: Re:surface extractor
>
>I use a Wasseroberflachenabzug or Taunus (it's German and I think that that
>is the name!!!! ) surface extractor that is self adjusting to cope with
>varying water levels.  It gurgles,  but I have never had a fish sucked
>thru.  It has a sliding two piece tube design and the top tube has a grate
>and a ring to trap air to keep it floating.  As the level drops, the top
>tube just slides further into the bottom tube.  Has about 4" of travel and
>that should take care of varying water levels between water changes/top
>ups.  Blue and white box, but cost 2 right arms and half a  leg!
>
>Alfred
>
>
>At 03:48 AM 10/15/99 -0400, you wrote:
> > >From: taylorjc2@juno.com
> > >Subject: Ehiem surface extractor
> > >
> > >Is anyone using the ehiem surface extractor?  Is it noisy.  Does it
> > >adequately skim the whole surface of the water?  Will it suck up fish?
> >
> >I'm using one, but only for lack of a better alternative.  It is noisy at
> >times (a clanking sound) when the water level is not just right, or there
> >is obstruction to the flow.  It skims the whole surface, but only for a day
> >or so, then leaves and other floating bits of plants would plug it up. I
> >have to clean out the intake tubes every couple of days.
> >
> >Ivo was working on an alternative a while ago.  How is it going Ivo?
> >
> >Hoa

Hi list
	There has been a thread about surface extractors  going on 
for a couple of days and I wanted to point to my site for anyone 
interested in building one of these units. The one I made is very 
easy and although I didn't know it at the time is based on the one 
that is described above. I must say that I didn't even know that the 
item described above even existed and this thing I made was created 
from my imagination. I created a page with directions and pics at 
http://www.vaxxine.com/martinhouse . There are only 3 things that are 
necessary to make this Fiddleless Surface Skimmer. A gravel vacuum, a 
piece of 1.5" pipe and a piece of styrofoam. That's it. Mine has been 
going for 2 months now and other than cleaning out the loose algae 
that gets trapped it is truly fiddleless. Any comments are 
appreciated.

Wayne Martin
wamart@vaxxine.com


Up to Plumbing and Filtration <- The Krib
This page was last updated 25 December 1999