You are at The Krib ->Marine/Reefs [E-mail]

./scrubbers

Contents:

  1. Algal Scrubber meeting
    by wil/shell.portal.com (Ville V Walveranta) (Mon, 19 Jul 1993)
  2. Algal Scrubber meeting
    by steve/rhythm.com (Steve Tyree) (21 Jul 93)
  3. [M] Small scrubber test, with predictions
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (11 Apr 1993)
  4. [M] Small scrubber test, with predictions
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (11 Apr 1993)
  5. Small Scrubber Test part I
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (27 Apr 1993)
  6. Small Scrubber Test part I
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (28 Apr 1993)
  7. [M] Scrubber Tank Update
    by laurence/cco.caltech.edu (Dustin Lee Laurence) (28 Jan 1994)

Algal Scrubber meeting

by wil/shell.portal.com (Ville V Walveranta)
Date: Mon, 19 Jul 1993
Newsgroup: alt.aquaria,rec.aquaria

	I went to listen to Mike Martin's presentation on Algal Scrubbers
	at a SFAS/Reef Study Group meeting last night. Having never run
	a marine tank (yet) the last suspicions I had about the algal
	scrubber (arisen by the conversations here, and having read the
	threads of earlier discussions in these conferences) are gone.
	Say, at least *his* display tank and a few other SFAS members'
	tanks were doing great using algal scrubber either alone (Mike
	Martin's tank) - or in combination with a skimmer.

	The doubtful comments on algal scrubbers often seem to suggest that
	the algal scrubber functions as a launching pad for the algal
	cells that seek out, and kill, the stony corals. There was no
	evidence of that, however, in their tanks. Mike's tank has been
	running last eight months using an algal scrubber as the only form
	of filtration. The nitrates are undetectable with a HACH kit, 
	green algae that was somewhat detectable in the tank before the
	introduction of the AS, has totally vanished (the tank has been
	running total of two years). He actually occasionally rips some
	green algae from the AS and drops it into the tank for the tang
	to eat with no ill effects.

	He stressed that he does not advocate most of Adey's ideas because
	Adey's ideology is to be able to [try to] maintain entire captive
	ecosystem, not to maintain a reef-environment in which most of the
	hobbyists consider the [good] looks of the tank to be important.

	I should mention that his tank currently gives home to several
	soft and stony corals, many of which are not at all 'hardy'. 
	All of them have grown substantially since the filtration system 
	was changed to algal scrubber-only. There is no detectable algal
	growth in the tank.

	The tank's maintenance schedule looks like this:

DAILY:
An addition of Kent Marine's Concentrated Liquid Calcium is made.  The 
amount varies but is typically 2 to 3 teaspoons per day.  (This is eight
to twelve times the recommended dose and was determined by trial and
error.)  Every other week the calcium level should be checked and the 
dosing of the calcium supplement adjusted up or down as needed. The
goal is a calcium level of 420 to 450 mg/l of calcium in water that
has a s.g. of 1.021 at 78 degrees F.

TUESDAYS AND FRIDAYS (schedule permitting):
I wipe down the front and sides of the aquarium. The back is left untouched.

WEEKLY:
Removal of visible detritus accompanied by a 10% water change using
Aquarium Systems' Reef Crystals salt mix to help with calcium 
replenishment. The carbon filtered tap water is mixed 24 to 48 
hours in advance and KH is tested and corrected to 16 degrees kH.

Testing of pH is performed. It is always between 8.2 and 8.4 so no 
adjustment is necessary.

Testing for KH is performed. If the KH is 11 degrees or less, I add one
dose of Aquarium Systems' Sea Buffer. The goal is to have the KH between
12 and 16 degrees, with 16 being ideal.

I add one teaspoon of Kent Marine's Strontium and Molybdenum Supplement.
This is the correct amount according to the directions, however, it is
not quite as frequent (they recommend one teaspoon every 4 days).

EVERY TWO WEEKS:
I remove about one third to one half the algae from the growth plates
and throw it away.

MONTHLY:
I check for nitrate and phosphate. None is detected. Ever.

EVERY SIX TO EIGHT WEEKS:
I change half of the Kent Marine Reef Carbon that is used in the hanging
backfilter. Total amount in use is approximately one cup.

EVERY THREE MONTHS:
The algae scrubber's sides are cleaned to remove overgrown algae.

All the pumps are disassembled and cleaned to restore their full
flow [he uses Eheim pump].

The bulbs in the canopy are replaced.

EVERY SIX MONTHS:
The bulbs in the algae scrubber are replaced.

RARELY:
(If I haven't faithfully followed my own advice from above) I will
remove a tuft of feathery macro algae from a rock or two in the tank.

[Sorry for any possible typos.. I copied that off Mike's handout]

---

	So, basically what I will do is to set up a tank with an
	algae scrubber that I will probably build myself to facilitate
	few changes that I think might prove useful, and with a 
	good protein skimmer that will skim all the water that returns
	from the sump and thus from the algal scrubber (just in case ;).

	I'd be interested in hearing any comments on this. 

	// Wil
--
 * Ville V. Walveranta      Tel./Fax.....: +1 (510) 420-0729  THIS IS ****
 ** 96 Linda Ave., Apt. #5   From Finland: 990-1-510-420-0729  HOW IT  ***
 *** Oakland, CA  94611-4838  (FAXes automatically recognized)  BEGINS! **
 **** USA                       Email....: wil-at-shell.portal.com          *


Algal Scrubber meeting

by steve/rhythm.com (Steve Tyree)
Date: 21 Jul 93
Newsgroup: alt.aquaria,rec.aquaria

In article <CAEFsE.C46-at-unix.portal.com> wil-at-shell.portal.com (Ville V Walveranta) writes:
>	I should mention that his tank currently gives home to several
>	soft and stony corals, many of which are not at all 'hardy'. 
>	All of them have grown substantially since the filtration system 
>	was changed to algal scrubber-only. There is no detectable algal
>	growth in the tank.

 Since you asked for comments- What type of stonies where doing well in
this Algae Scrubber reef? There is a big difference between large polyed
stony coral and small polyped stony coral. Many large polyped stonies are
found in turbid areas along with the turf algae that Adey has noticed.
Many small polyped corals are found on fore reefs where very little turf
algae is found in nature. Many of us have yet to see documents or peer 
reviewed articles or pictures of small polyped stonies surviving comfor-
tably for long periods in Reef Scrubber systems. The recent photo of Adey's 
home reef which appeared in FAMA (July 93 page 2) had an encrusting stony 
in the vicinity of a large bladed macroalgae. This is not good for the 
coral. Either his home reef lacks proper turf algae consumers or he is not
pruning the growth properly. We are concerned about the corals, right ?
 There may be a place for this system, we should not oversell it though.
If it is not the best system for small polyped stonies, we should not
hesitate to state it as such. It may have a place in supporting fish, soft
coral or large polyped stonies. The educational values in teaching eco-
system dynamics is highly valued. 
 note - In the Great Barrier Reef only _Pocillopora damicornis_ and
        _Turbinaria_ small polyped coral species were found to compete 
        well with macro-algae. (source-Corals of Australia and the 
        Indo-Pacific)
 ps - I have a berliner 180 gallon reef with at least 10 small polyped
      stony coral species. Total specimen count greater than 20.

 Steve Tyree - Reef Breeder


[M] Small scrubber test, with predictions

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 11 Apr 1993
Newsgroup: rec.aquaria

I guess I'll have to put up, since I haven't exactly been shutting up.
I've been complaining that no one is interested in actually doing any
comparative tests, but I said that I couldn't afford the time or money
either.  Well, I was in the bedroom this morning looking at the ten
gallon bare tank there, and I realized that that wasn't really true.

The tank right now has no filtration; it contains four small fist-sized
pieces of live rock and an airstone to turn the water over.  It was
originally an experiment, and right now is a refuge for a single 1"
goby that was being picked on by a clownfish in the main tank.  It
actually maintained a minimal load of one disk anemone and three or
four anemones about half the diameter of a penny quite well (temperate
anemones that I saved from death, but they may die with only window
light), but the waste from that one goby is starting a good hair algae
growth.

I've been telling myself to give it a real light hood and a small skimmer, and
this morning it hit me that I could just a easily give it a hood with
a built-in algal scrubber.  It's money and time I'd have to spend anyway,
so there is no reason not to.  I'm very curious about what will happen,
and besides that I ought to put up some effort where my mouth is.

So I'm setting up the cheapest full featured Adey-style tank possible.
It will be a somewhat deeper water concept than usual, so I need only
minimal bluish lighting for the tank (a lot of people haven't noticed
yet that deepwater reefs are just as nice, and don't require expensive
lighting.  That way, I only have to buy lots of light for the scrubber.
I think htat I can build a hood with a tiny scrubber and refugium for
very little money, and if one of two ideas work out I can also make a
non-lethal mechanism to lift water the couple of inches I need for very
little.  If enough interest is expressed, I'll post a sketch of what
I plan to do, and how I plan to maintain it.  I'd appreciate some idea
of how much people want to hear about it, because I have no intention
of boring the whole net further with it if the interest is not there.

I plan to just run it without adding much for a while.  If I like the
water parameters, I can add live rock, and if everything continues to
go well I'll ultimately attempt to keep some deepwater reef creatures
like sponges and Tubastrea type corals.  This will be a particularly
good test, because the main system will have a deep-water section that
I plan to put similar animals in, allowing some measure of comparison
(to the degree that a comparison of a ten-gallon system with an 80+
gallon system is fair).

Adey is particularly proud of the way filter-feeders do in his tanks,
so sponges and things should give the scrubber a chance to show off
it's strengths.  Conversely, if it does well I'll do my best to get
some difficult to keep deep-water corals (I don't remember if
Tubastrea are hard to keep or not, though I think not).  Anyone know
any reputedly impossible non-photosynthetic invertebrates that I can
get ahold of if this thing works well?

Last, some predictions are probably in order.  I predict that the tank
will maintain the filter feeders as well or better than the main reef
in developement.  I think that the inorganic nutrient levels will drop
to unmeasureable on my kits, but the water will be heavily loaded
compared to what the main system will run at.  Finally and most
importantly, I claim that it will not be capable of maintaining corals
and other sensitive invertebrates as well as the main system will.

If these predictions don't work out, I'll...well, I guess I could buy
myself a beer.  Kinda pathetic, isn't it?  Any suggestions?  I refuse
to shave "Adey is God" or anything on my head, even if it does work.  :)

I don't know how long it will take me start this.  If only my advisor
would give me some time to build the little thing, I'd be all set.
Unfortunately, I'm having a hard time figuring out how to convince him
that this counts as progress toward my degree.   :)

-- 
Dustin                         "I contradict myself?  Very well, I contradict
                           myself.  I am vast; I contain multitudes."

laurence-at-alice.caltech.edu


[M] Small scrubber test, with predictions

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 11 Apr 1993
Newsgroup: rec.aquaria

laurence-at-cco.caltech.edu (That's me) errs:

>....I think that the inorganic nutrient levels will drop
>to unmeasureable on my kits, but the water will be heavily loaded
                                                    ^^^^^^^^^^^^^^
>compared to what the main system will run at.

Eh?  That should be "heavily loaded with dissolved and possibly
particulate organic matter."  Those responsible for the error have
been executed with teeny tiny dull knives.

-- 
Dustin                         "I contradict myself?  Very well, I contradict
                           myself.  I am vast; I contain multitudes."

laurence-at-alice.caltech.edu


Small Scrubber Test part I

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 27 Apr 1993
Newsgroup: rec.aquaria

As I promised, here's the first section of a report on our small
scrubber test.  We have chosen to emphasize the ecological concepts
involved, since this approach may not be familar to many net.readers.
If people find this sort of discussion interesting, I'll continue to
post as things develop.

One more thing; this is typeset in LaTeX.  I don't think that this
should be to distracting, since almost all of it is just text, but if
I get too many complaints I'll consider removing all of the LaTeX
directives from future sections.

---------------

\documentstyle[makewider]{article}

\title{\protect\Large A Small Scale Test of a Scrubber-Based Microcosm}

\author{Dustin Laurence and Teresa Moore}
\date{April 27, 1993}

\renewcommand{\thesection}{\Roman{section}}

\begin{document}

\maketitle

\section{\protect\large Conceptualization and Discussion}

This project is designed to test the operation of aquaria of the type
described in Adey and Loveland's {\em Dynamic Aquaria}.  Our preference
would be to set up a second system identical to our planned multi-tank
Berlin system except in the choice of filtration, but this is quite
impossible for us in the forseeable future.  The small system that is
possible will inevitably be a far poorer test of the success of a reef
based on scrubber filtration, but in compensation it may be a rather
severe test of the scalability of their methods to small tanks and
budgets.

As our budget for a second aquarium project is vanishingly small, this
project will involve the conversion of pre-existing ten-gallon tank.  No
tank purchase will be necessary, and the small size means that stocking
and equipping the tank will be much cheaper.  For similar reasons, nearly
all of the equipment will be homemade.

Ecosystem diversity is a function of available space, so it must be
admitted at the outset that no model this small can hope to be a
faithful representation of the original; the more complex the ecosystem,
the poorer the accuracy is likely to be.  In spite of this difficulty,
the ecosystem we choose to model is one of the most complex, that of a
tropical coral reef.

There are several reasons for this choice: much of the motivation for
this experiment derives from the debate over the suitability of scrubber
methods for reef organisms; our personal interests are focused on marine
aquaria and reefs in particular; all other marine ecosystems that we
would have access to would be temperate California ecosystems requiring
an expensive chiller; and the fact that we have a quasi-reef system now
and a multi-tank reef in progress means that in the worst case the
inhabitants could be transfered to another tank.  Perhaps most
importantly, it allows direct comparison with the same or similar species
in other tanks, to the degree that any such comparison can be fair with
such a small tank.  We should note that the success of systems such as
Julian Sprung's 15g reef give some indication that small systems can
enjoy good success, at least as aquaria.  As an ecosystem simulation, our
goal will simply be to do as well as possible under these conditions.

Every modeler must choose certain communities to model most closely, by
the inclusion of as many representatives of as many guilds in those
communities as possible, and others to model by less accurate methods,
such as by feeding or filtration.  Preferably, this choice is based on
the relative importance of each community to the health of the ecosystem
as a whole, but even the most biologically important communities may be
excluded as impractical or impossible.  The best example is perhaps the
off-shore open water community, so crucial to the health of a coral reef
but requiring a vast volume of water.  The small size of our model
restricts our choices even further, and probably makes these choices
still more critical to the ultimate success of our model.

It is important, then, to choose a focus for the model to guide the
choice of inhabitants and filtration.  At first, a model of a shallow
cave inhabited by creatures normally found on the darker deep reef is
very attractive.  Such a community is perhaps somewhat isolated in
nature, being a small outpost of the deepwater community isolated by a
surrounding shallow-water community.  We suspect that this natural
isolation may make it a better candidate for compression into a small
isolated aquarium.

Also, our main reef project will include a separate deep tank, so
limited comparisons between similar species would still be possible.
The validity of these comparisons is open to question, however, both
because of the very different size and filtration of the systems and
because the deepwater/cave tank in the main system really is connected
to a larger shallow-water tank.  Finally, as a deepwater community is
not directly dependent on photosynthesis, the cost of lighting would
be greatly reduced.

Some thought, however, shows that this idea is not as attractive as it
seems.  The problem involves the inclusion of primary producers.  A
cornerstone of the approach that we are testing is to reduce nutrient
concentrations by primary production (photosynthesis) rather than by
nitrifying bacteria, since the former process dominates in nature; this
is the basis of Adey and Loveland's insistence on the use of algal
scrubbers.  Therefore, the scrubber will need good lighting regardless
of the type of community, and the cost of supporting photosynthesis
cannot be avoided in any reasonable simulation.

Also, on a real reef photosynthesis rapidly super-saturates the water
with oxygen during the day and depletes carbon dioxide and carbonic acid
levels far below equilibrium.  At night, the reef respires, depleting
oxygen and producing carbon dioxide far faster than they can be exchanged
through the surface waters over the reef.  The reef does not suffocate
due to the influx of off-shore water saturated with oxygen and CO2.  For
a good simulation, then, then we want oxygen super-saturation and carbon
dioxide depletion during daylight, and and near saturation levels during
the night.

The same processes that produce this non-equilibrium behavior on a real
reef behave similarly in a standard, strongly lit reef aquarium.
Therefore, it is the nighttime behavior that we must concern ourselves
with.  The standard method of achieving nighttime saturation in a tank
of the type we are building  is to run the algal scrubber at night, so
that it's algal population in a sense simulates the entire off-shore
phytoplankton community.

If the tank is to represent a dimly lit cave, however, then the daytime
primary production cannot take place in the tank.  If a scrubber were to
run on the usual nighttime cycle, then the oxygen levels would be
reversed, with the higher levels at night.  Many organisms depend on a
diurnal cycle, and having the oxygen (and carbon dioxide) levels
reversed relative to the other diurnal signals could have significant
effects on many animals.  Without better information on the subject,
this inversion seems to us to be an unacceptable compromise.

A final argument against the cave/deep tank idea is a personal one; the
criticism is often made that algal growth in a reef tank cannot be
controlled with a scrubber going, and this cannot be fairly tested
unless the tank is well lit.

A few alternatives present themselves.  One is to run the scrubber
during the daytime, in phase with the dim lighting.  This may work, as
long as the tank is sufficiently lightly loaded that nighttime
respiration would not lower the oxygen levels too drastically.  However,
it is the nature of small tanks to be stocked relatively more heavily
than larger tanks, and the presence of the respiring community of algae
in the scrubber would exacerbate the problem.

A second alternative is to run two scrubbers.  A larger one during the
day would model the activity of the local reef community which surrounds
our fictional cave, while a smaller one lit during the night would again
model the offshore phytoplankton community.  This seems attractive both
because it would protect the system against oxygen depletion and also
because it demonstrates the modeling process in a clear and interesting
way.  However, it would require more lighting than the previous idea.

A third alternative is to give up the dark cave idea entirely and set up
a standard, well lit tank.  This has several obvious advantages, but may
require more lighting than either of the previous possibilities.  Also,
the cave theme seems to lend a more interesting and unique touch to the
project.

A fourth, idea is to set up two connected tanks, a strongly lit one
supporting one with dim, blue lighting.  This would be interesting, but
it is impractical for us at this time to build another multi-tank system.

At this point, we have not decided which approach we will take; some
other issues can be resolved before we need make a final decision.  In
particular, all of the water pumps sold for use in the hobby are
centrifugal pumps.  Adey and Loveland make the claim, however, that these
pumps kill small plankton as they pass through.  Since we would prefer to
include as much of the planktonic community as possible, one of the most
important issues we will face in testing their claims is whether a
non-centrifugal pump can be rigged up with reasonable cost and effort.
This will be the subject of our next installment.

\end{document}


-- 
Dustin                         "I contradict myself?  Very well, I contradict
                           myself.  I am vast; I contain multitudes."

laurence-at-alice.caltech.edu


Small Scrubber Test part I

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 28 Apr 1993
Newsgroup: rec.aquaria

laurence-at-cco.caltech.edu (Dustin Lee Laurence) writes:

>One more thing; this is typeset in LaTeX.  I don't think that this
>should be to distracting, since almost all of it is just text, but if
>I get too many complaints I'll consider removing all of the LaTeX
>directives from future sections.

>---------------

>\documentstyle[makewider]{article}
                ^^^^^^^^^

But of course, I didn't include the makewider.sty stylefile.  Apparently
it's not a standard stylefile, but one written by the local TeX guru.
I'll include the lines explicitly in future articles, but meanwhile here
is makewider.  Of course, if you want margins like the ridiculously large
defaults (at least on our system), you don't need this...  :)

-------------------

% By Michael J. Malak

\addtolength\topmargin{-1.0 in}
\addtolength\textheight{2.0 in}
\addtolength\textwidth{1.0 in}
\addtolength\evensidemargin{-0.5 in}
\addtolength\oddsidemargin{-0.5 in}

-- 
Dustin                         "I contradict myself?  Very well, I contradict
                           myself.  I am vast; I contain multitudes."

laurence-at-alice.caltech.edu


[M] Scrubber Tank Update

by laurence/cco.caltech.edu (Dustin Lee Laurence)
Date: 28 Jan 1994
Newsgroup: rec.aquaria,alt.aquaria,sci.aquaria

Some time ago, as no doubt no one remembers, I mentioned that I had
been goaded into building a small algal scrubber based marine tank
(mostly following Adey, except where that isn't practical).  The plans
have changed considerably since then, but it is nearly finished (at
last, at last).  I'm too pressed for time to say much, but the current
version is a 40g tank with a scrubber and settling tank/refugium in
the sump.  No mechanical filter, nothing but the scrubber and settling
tank.

The tank will be a reef, kinda; it will get as much live rock as we
can afford, which may or may not be much for a while.  But eventually,
it should qualify as a small reef.  It will get a nice calcareous sand
substrate, later if not sooner.

The water drains through a standard (but homemade, like everything
else) syphon & standpipe overflow, and goes to the scrubber. The
scrubber is in a dump bucket which is lit by two 2 foot HO
fluorescents.  I'll have to try to post what I learned in making my
first dump bucket.

The dump bucket dumps into a settling tank, with some baffles to slow
down the water and make sure that there are quiet spots for debris to
settle.  This will be rarely or never cleaned out--it is as much a
refugium as it is a settling tank.  I imagine that we will put some
serpent stars and other detritivores here as soon as we see
significant debris.  We may even put in some rocks and substrate to
make it a full-fledged refugium.  It's an experimental tank, so I
guess we'll just...experiment.

It then overflows the settling tank into the other half of the
homemade, acrylic sump (this half is the actual sump, dynamically
speaking), where it is pumped back to the tank.  For now, the pump
will be a small Eheim submersible pump which was on hand.

To save some money and time, the tank doesn't have a light hood yet.
It will initially just get window light.  eventually, it will be lit
by four 3' HO tubes.  The ballast is already wired in, waiting a hood
for the tubes.

So: the tank is considerably larger than we'd planned at first, which
is good.  However, the non-centrifugal pump idea is gone.  On the
whole, this should ultimately be a fairly good implementation of
Adey's ideas.  Should be interesting to see what happens.

Dustin, slowly putting his money where his mouth is (I said Adey's
        ideas would not work well for delicate stony corals, for those
        who want to keep score).


Up to Marine/Reefs <- The Krib
This page was last updated 29 October 1998