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That Darn Plant Tank: Email Correspondence


  1. lighting
    by Erik Olson <eriko/> (Mon, 2 Mar 1998)
  2. hanging the light
    by Erik Olson <erik/> (Wed, 28 Oct 1998)
  3. bulkheads in glass
    by Erik Olson <erik/> (Tue, 3 Nov 1998)
  4. That Darn Plant Tank
    by Erik Olson <erik/> (Wed, 6 Jan 1999)
  5. reflectors
    by Erik Olson <erik/> (Fri, 14 May 1999)
  6. That Darn Planted Tank - Plumbing Question
    by Erik Olson <erik/> (Wed, 7 Jul 1999)
  7. Lighting Hood
    by Erik Olson <erik/> (Sat, 14 Apr 2001)


by Erik Olson <eriko/>
Date: Mon, 2 Mar 1998
To: Janina <paaschjc/>

On Mon, 2 Mar 1998, Janina wrote:

> Eric
> If it isn;t too  much trouble, do you think you could give me some more
> details on how you build the hood and installed the lights.

OK. :)

I'll assume you've already looked at my "That Darn Plant Tank" article on
the Krib, which covered the basics.

> Does it
> actually rest on the tank, or hangs from the ceilling. 

Hangs from ceiling, but it could just as easily sit on the tank (in fact
it did for several weeks before I drilled the holes).

> For the lighting set
> up, you jsut have an instant start ballast and cables going to the lights?


> Are there end caps involved? 

No, instead I used end clips, similar to the ones used in many shoplights
& other fixtures.  They were much cheaper than end caps ($2-3 per
pair).  I screwed the clips directly into the canopy.

> I have not tried this before, so I don;t know
> exactly what is involved. The shop lights have everything hidden away so I
> can;t see how it is put together.

Depending on the manufacturer of the shoplight, you might be able to take
it apart.  If it's Lights of America, you're stuck, though.

> How many lights can you power with one
> ballast?

two or four.  Interestingly, the cost is only a couple bucks more for the
four-light version.

> How much do they usually cost?

$20-25 for the ballasts.

> What type of T8 do you use? Full
> spectrum, wide spectrum?

I've mostly used Sylvania FO32-750  (CRI of 80, color temp 5000K)
 and sylvania FO32-765 (CRI of 80, color temp 6500K).  They're cheap, only
about $4-5 per bulb, and are fairly good at rendering the colors.  I have
one tank with FO32-950's (CRI 95, color temp 5000K), and they look no
better than the cheap bulbs but cost me $12 each.

  - Erik

Erik Olson				
eriko at

hanging the light

by Erik Olson <erik/>
Date: Wed, 28 Oct 1998
To: CPike48201/

On Tue, 27 Oct 1998 wrote:

> Hello Erik, I just read your article on the 75 gallon. I have one myself. When
> you hung the light from the ceiling did you use plant hangers and chain? That
> is what I am going to use. 

Yes, I have a pair of hooks with toggle bolts that hold it up.  Since the
ballasts are kept off the hood, it's fairly light.

> What holds the hood up while you work on the
> aquarium? 

I just pull the chain up a few inches onto the hook, so the light is
suspended about a foot above the tank.  I keep the lights on, so I can
actually see into the tank!

> Just curious what you had used and how good it works? And with the
> plumbing how did you regulate the waterflow between the tank and the sump not
> to overflow one or the other?

When you use a siphon box and sump under the tank, the tank is always kept
at the level of the siphon box (any new water spills over into the box).
The faster you pump water into the tank, the faster it overflows into the
sump. The water level in the sump gradually gets lower due to evaporation,
so it's important to do those water changes and replenish the excess
before the sump level gets too low.

To keep the water returns from back-siphoning everything out of the tank
during a power outage, I have small holes drilled near the top that will
break the siphon.  I have a new design I'm going to try out soon involving
ping-pong balls and PVC that should be 100% effective.

   - Erik

Erik D. Olson
erik at

bulkheads in glass

by Erik Olson <erik/>
Date: Tue, 3 Nov 1998
To: CPike48201/

Good question on the bulkheads.  If I'd thought about it more, I probably
would have gotten something drilled.  I regret this now.  It's true, glass
companies won't guarantee the tank won't crack, but on the other hand lots
of people do this for their fishrooms...

I have just designed a nice combo check valve + antisiphon system that now
takes care of unexpected power outages from the water return side (keeps
the tank from emptying its contents back into the sump).  But the overflow
is still a bit problematic and I worry about leaving the tank alone for
too long.  Interestingly, it's gotten much better since I jacked up the
flow rate!

I use ball valves on the Quiet One in order to regulate flow (you can see
the drawing and photograph on my "That Darn Plant Tank" article). In
retrospect I am very GLAD that I went a bit high on the pump, because I
really hated the wimpy little thing I used on the previous tank (the
Aquaclear-802 powerhead, which frequently refused to restart after power
outages or water changes). Make sure to take into account the head when
buying the pump; may do 500gph at zero feet of head, but at 3-4...

  - Erik

On Tue, 3 Nov 1998 wrote:

> Erik,
>     I noticed how you didn't go with the bulkheads on the 75.  Why didn't you?
> I found a glass company that will cut my 75.  But they're not 100% sure that
> it won't crack.  Is that why you didn't try the bulkheads and used the
> overflow box instead?  And also do you regulate the flow on your return pump
> since it is 1140 gph?  I can get a smaller (500gph) pump.  Thanks for your
> time.
> Chris

Erik Olson
erik at thekrib dot com

That Darn Plant Tank

by Erik Olson <erik/>
Date: Wed, 6 Jan 1999
To: Paul Leuba <pleuba/>

On Wed, 6 Jan 1999, Paul Leuba wrote:

> Erik,
> First, please pardon me for emailing you privately...

No problem!

>     1.. Which model of Dupla heating cables did you purchase for your
> 75 gal?  Are you still running them 24hours a day?

I beleive it was the 50-watt cable.  I actually purchased it for my
previous (smaller) tank, but they were out of the 100-watt unit I wanted
for this one.  I unplug it during the summer but otherwise leave it on.

>     2.. What transformer did you use?  Dupla's or an aftermarket? 

Definitely surplus.  24-volt 4 AMP unit.  Cost me $15 at an electronics

>     3.. What thickness of maple plywood is your light hood made out of?

Pretty thin actually, I'm tempted to say 1/2".  Definitely not 3/4".

Hope this helps.

  - Erik

Erik Olson
erik at thekrib dot com


by Erik Olson <erik/>
Date: Fri, 14 May 1999
To: ikw/

Hi Gordon,

My use of the trapezoid hood was just an improvement over the crummy
"boxy" hoods, not an attempt to break any records for focusing into the
tank.  There are several areas I could have done better if I was trying to
"go the last mile": If you look at the cross-section picture in the
article, you can see I don't even have reflectors for the individual bulbs
(something I was going to add if I had time... which I haven't).  And I
painted the inside rather than using silverized mylar; though it reflects
a very similar percentage, the paint scatters it somewhat randomly, while
the mylar would focus it.

If you are going for absolute maximum reflectivity, I would trust a
parabolic type such as this "spyderlite", over each bulb.  But I would
also follow the dimensions and placement very accurately.

    - Erik

On Fri, 14 May 1999 wrote:

> hi eric,
> in "That Darn Plant Tank" you mention that trapezoid shape 
> reflectors are the best.  i have tried a mcdonald's m which i did not 
> think worked well and am using a shape which i want to think is 
> efficient and is based on a design by digital oceans called the 
> spyderlite. by my light meter measurements i guesstimate a light 
> increase of about a 30 percent or more vs no reflector. alot of light 
> seems to be reflected out of the aquarium and i would like to try a 
> hybrid spyderlite trapezoid. 
> the statement that trapezoid reflectors are best... 
> (hope i am not misquoting you here)....based on a visual evaluation 
> and/or a comparison of light levels? 
> i thankyou in advance. 
> sincerely,
> gordon watanabe

Erik Olson
erik at thekrib dot com

That Darn Planted Tank - Plumbing Question

by Erik Olson <erik/>
Date: Wed, 7 Jul 1999
To: txice <txice/>

On Wed, 7 Jul 1999, txice wrote:

Hello Erik,

Please forgive the intrusion, but I was wondering if you could help me out.

I am in the process of setting up a planted aquarium in my living room. I have a 75 gallon Oceanic aquarium. I have already built a stand for the tank, and have purchased parts for, and assembeled, a CO2 system consisting of a 20lb CO2 bottle, two-stage regulator, a Nu-Pro needle valve and associated fittings needed to piece the whole thing together. I have already had some plans for a lighting fixture drawn up, but haven't started on the construction of the hood yet. I have been having alot of trouble designing a filtration system. Browsing the web for some ideas, I ran across your article "That Darn Planted Tank" and found it very interesting (especially since you also used a 75 gallon aquarium). I read the section on Plumbing and Heating, but wasn't able to grasp a clear picture of how your plumbing system was set up. It sounds very interesting, and something that I might want to consider for my setup (or at least a close adaptation). Is there anyway you could provide me with a more detailed description/schematics of how the whole system is setup?

I would be very appreciative.


Tim McGovern

Hi Tim,

There's not much too the plumbing... there's an overflow siphon that hangs off the back of the tank (described in my other planted tank article "The Almost Affordable Aquarium" (see the diagram for dimensions... it's size was the exact fit for a $2 aquaclear-300 foam.))

What's not shown in any of the diagrams is how I do my bulkhead fittings, which are used at the bottom of the prefilter (drain), and where the pump is attached to the sump. I've enclosed a GIF I drew up for you. In the new tank, I use 1" PVC fittings at the bottom of the prefilter, because 3/4" was too small and gurgled all the time.

Nowadays I also tend to hollow out a small hemisphere of the foam right where it sits on top of the drain hole, in order to guard against clogging.

The sump's just an acrylic box; looks just like an acrylic tank. Imagine a wet-dry filter with everything removed. There's another bulkhead fitting in the side, near the bottom; you can see this in all the photos on the site. 3/4" PVC. The inside part of the fitting is not hacked up with a saw like the one in the overflow. This runs to the pump directly through the length of PVC (with a male threaded adapter on the other end). I think this fitting has O-rings on both sides because the height of the bulkhead hole has to be critically aligned with the intake on the pump. If I were redoing the whole thing today, I'd probably cut the PVC pipe in two and add a small length of flexible vinyl tubing clamped between, just to add more stability.

The other return does to a drip irrigation manifold and into the CO2 injector, back into the sump.

If this isn't more clear, I can probably take some digital pictures of the whole thing later today.

- Erik

[Bulkhead Sketch]

Lighting Hood

by Erik Olson <erik/>
Date: Sat, 14 Apr 2001
To: "John T. Fitch" <JTFitch/>

Right, there's a standard glass cover underneath.  The flap on the light
hood opens, and there's just enough clearance underneath that the glass
lid can be opened for food to be stuffed in, or a Magnum 350 can be
sitting there polishing water (every few months when I do a massive
pull-up of plants).  

If you open the flap all the way, you will be staring right at the first
light.  It's not blinding, but it's a bit high.
Now if you're going to do the same hood design, but use 96 watt cf's, you
should also have the AH Supply Miro-4 reflector as part of the kit, right?
Mounting the reflector in the hood will keep the light out of your eyes..
Incidentally, If I were retrofitting with the AH Supply lights, I would
probably route some grooves in the top of the hood for air circulation.

One last point, and that is about the hood "sitting on the tank".  My hood
doesn't sit on the tank, it's actually suspended by decorative chain from
the ceiling.  So in essence it "floats" just above the tank.  Minor
difference, but it adds a little more ventilation that I wouldn't
otherwise get with it sitting directly on the tank.

  - Erik

On Sat, 14 Apr 2001, John T. Fitch wrote:

> Erik:
> Thanks for the prompt response.  But now I'm confused.  If there's a glass
> cover below the hood, is it the conventional kind that's hinged so that you
> can open it?  So, am I correct that you fold back the front of the hood on
> its piano hinge and then lift up the front panel of the glass cover.  Is
> that correct?  And, if so, I assume there must be enough height in the hood
> below the lights so that the inner glass can be opened?
> One other minor point: When you open the hood, aren't you staring right into
> the lights?  Or do you have some kind of baffle that isn't shown in the
> picture?
> I really like the basic idea; it's just that if I'm going to build one, I'd
> like to do it right.  Thanks.
> John
> John T. Fitch
> 4 Canal Park #712
> Cambridge, MA  02141
> Tel/Fax (617) 494-4882
> E-mail:
> Web Page:
> ----- Original Message -----
> From: "Erik Olson" <>
> To: "John T. Fitch" <>
> Sent: Saturday, April 14, 2001 12:14 AM
> Subject: Re: Lighting Hood
> > Hi John,
> >
> > Actually, my tank does have a glass cover below the hood.  Yes, it
> > attenuates some of the light.  But the tradeoff is that without it there
> > is HORRID evaporation and potential condensate on the fixture.
> >
> >   - Erik
> >
> > On Fri, 13 Apr 2001, John T. Fitch wrote:
> >
> > > Erik:
> > >
> > > On your page, you
> show
> > > a cross section of a trapezoidal hood (see attached .GIF file).  I would
> > > like to build something like that for a 96-watt compact fluorescent kit
> I've
> > > just bought from AH Supply.
> > >
> > > But, since yours appears to sit right on the tank, without a glass cover
> > > under it, isn't condensation and/or corrosion a problem?  My present
> > > All-Glass canopy specifically warns "Do Not Use Over Open Water."
> > >
> > > Would appreciate your comments.  Thanks.
> > >
> > > John
> > >
> > > John T. Fitch
> > > 4 Canal Park #712
> > > Cambridge, MA  02141
> > > Tel/Fax (617) 494-4882
> > > E-mail:
> > > Web Page:
> > >
> > >
> >
> > --
> > Erik Olson
> > erik at thekrib dot com
> >
> >

Erik Olson
erik at thekrib dot com

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