# Algal Turf Scrubber

## Building an ALGAL SCRUBBER for marine aquaria...

### by erno-at-mrcnext.cso.uiuc.edu (Erno Pena) Date: Fri, 27 Mar 1992

Algal Scrubber for Marine Aquaria

Sometime this summer, before I build my 75 gallon wooden tank, I plan on
building an algae scrubber for marine aquariums. I've seen quite a few
already, and I know there is much discussion about them in the book _Dynamic
Aquaria. I hope someone out here can offer some advice on my design.

This is my plan: I have an 12 gallon shallow plastic bus tray about 8 inches
deep and 24 inches long. I will mount two bulkheads at opposite sides for
water intake and output. There will be a Tri-Lux or similar plant fluorescent
lamp above. The water will be about 5 inches deep and will be fed by gravity,
which should provide a slow circulation. The water from the overflow box and
prefilter will be split, with some going into the scrubber, and the majority
into the drip plate. The water will travel through the scrubber and out into
the drip plate.

So far this is the easy part. The hard part is making the screen on which the
algae will grow, and actually seeding the scrubber with algae.

I plan to use fiberglass screen formed into a wavy pattern that affords me a
greater surface area. I will take some thick, stiff, plastic coated wire,
form it around the screen into a wide wave with about an inch between crests.
The water will flow down the troughs of the waveform instead of through. I
chose the screen because I've seen pictures of scrubbers using screens, and
because it will also allow water to flow through it, through a wall of algae.

Once the scrubber is built, I'll seed it by going to the local fish store and
asking them to take a small bag and fill it with water and a small bunch of
green hair algae from their reef tanks. I'll take the scrubber, attach hoses
to the in- and outlets and connect them to a small powerhead to circulate the
water, add the starter algae culture to the screen, and let the light grow
the rest. There should be a rather lush growth in a few weeks, by which time
I should have my tank built and cycling.

The only maintenance for this scrubber should be periodically adding
phosphates and removing excess algae. This excess algae can be fed to your
fish, making the scrubber double as a food machine. Other than this, I don't
see much more maintenance required.

Well, that's my plan. I included diagrams below for clarification. I hope it
works. What do you think? Is there anyone out here with experience building
these things? There are a few questions I have however.

- Are there places where I could buy a good, abundant algae starter
culture to speed things up?

- I plan on having only two fluorescent bulb for lighting. Should I get
more?

- I plan on adding some phosphate for additional fertilization for just
this scrubber. Good idea, right?

- Exactly what type of algae should be grown in this scrubber? I forgot
what _Dynamic_Aquaria_ recommends.

- Is there a general size requirement for scrubbers for a given tank
volume? (i.e. would this ~10 gallon algae scrubber be able to support
a 75g tank?)

I can't think of any more. Please email or post your thoughts and criticisms.
I'll post a summary of all the comments.

Thanks.

erno

top view
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--

E r n e s t o   F.   B.   P e n a
---------------------------------
erno-at-uiuc.edu   NeXTmail accepted


## [M][R] Live Rock Farming

### by steve-at-celia.UUCP (Steve Tyree) Date: 10 Sep 92 Newsgroup: rec.aquaria


The new issue of FAMA has a very interesting editorial article. I forgot
to bring the magazine into work so I will try to remember the details.
A new company has formed which sells reef breeding systems based on the
algae scrubber tanks described in the Academic Book Dynamic Aquaria. These
systems unfortunately sell for 100,000 for the first 625 system which in-
cludes support and other goodies, each additional tank costs ~ 20,000 US.
The company name might be ECO-Systems or something similar. The first systems
are primarily intended to grow and farm live rock which can be sold and
used as the base rock for captove reefs. They predict that about 10,000 $of live rock can be seeded and sold per year. The system apparently is de- signed to allow the entire food chain (planktons) to exist. This is no doubt due to the algae scrubber method of filtration. The author also men- tions that a similar system is being used in the Australian Great Barrier Reef Park, and that synchronous coral spawning has occured in the tank with spawning on the reef. This was reported here also by Jamie Oliver. He did not mention the algae scrubber system however. Anyway, the price of the system is steep but it sounds like an excellent idea. Apparently the company wants to establish locally based live rock breeders who also might be used as distributors for other captive breed reef organism. The system themselves are quoted as being capable of pro- pagating many reef organisms. Its sounds like they may be hyping the ca- pabilities of the system a little however, I applaud the efforts. Imagine, we could purchase captive grown live rock without nasty organisms in them. Steve Tyree - Reef Breeder  ## Small Scrubber Test part I ### by laurence-at-cco.caltech.edu (Dustin Lee Laurence) Date: 27 Apr 1993 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  ## Dynamic Aquaria by W.H. Adey ### by jamieo-at-gbrmpa.gov.au (Jamie Oliver) Date: Wed, 7 Oct 1992 krogers-at-javelin.sim.es.com (K. Rogers) writes: >tse-at-ra.nrl.navy.mil (Anthony Tse) writes: >>>I seem to be under the impression that Mr. Adey was rapidly discounted by >>>the industry in general and by people on the net. Am I right? If so, why? >> >> I for one don't believe in algea scrubber. As for why, some of us >>get to see his algea scrubber in action (Museun of Natural History in >>DC) and it's not a pretty sight. If my tank look anything near as bad >>as his, I would have quite the hobby long ago. However, do keep in mind >>that I don't think he is interest in a good looking tank, he's more >>interested in a scientific research on ecosystem. >Yeah, I've been perusing the his book as time's permitted and it's >clear from the outset that he's interested in mimicing real ecosystems >as closely as possible, not have a hodge-podge of inverts and fish >from around the world which look pretty in the living room. >He also has one major strike against his tanks in the Smithsonian: the >cooling of the building is more or less defunct. You could tell from >his book (between the lines) he was really frustrated about it as his >tanks were getting regularly stressed in a bad way. No mention was >made of using a seperate chilling unit. >One other thing from his book is they (at least were) use 3700-4200K >MH bulb -at- 50-60% CRI. This is not the best light to view things by... >At any rate, Anthony, I'd like a (reasonably) detailed description of >the Smithsonian tank some time. What exactly bugged you about it so >much? I'll probably never get to the DC area so I'll not be able to >see it myself. In particular I'd be interested if the tank's in poor >shape because of the algae scrubber and other basic ideas he has or if >it's due to poor maintenance, the cooling problem, general lack of >funds which plague such institutions, etc. I guess I'd have to see >several tanks set up along his lines for comparison to answer that >question. >If I won't get to DC I *really* won't get to Townsville to see the >Great Barrier Reef Park's 700,000 gallon tank using many of his >principles. Nobody can complain about that tank as the corals spawn >synchronously in it just like in the ocean on the other side of the >wall. Maybe Jamie could give us a short run down on that system some >day (time and interest permitting.) >-- >Keith Rogers >krogers-at-javelin.sim.es.com Let me say at the outset that I work for the Great Barrier Reef Authority which runs the GBR Aquarium, but I am not in the Aquarium section, rather I am in the Research & Monitoring Section. The view expressed here may not necessarily be those of the staff of the Aquarium, and might not even be 100% correct....... The GBR aquarium was indeed built using the same principal as Adey's system. It basically a scaled up version. Fish do very well in the aquarium (I understand) but corals are definately a problem. Most corals eventually die, although this takes 6-12 months. Some corals (particularly fleshy massives) do pretty well and the Hydorzoan coral Millepora has been observed to grow quite rapidly and increase its area of coverage several fold before eventually dying (probably due to temperature stress in the summer). The problem with coral mortality is severe enough that the collection of Acropora corals is now scaled down to a minimal level. Corals have indeed spawned in the aquarium, but this is a bit misleading since the corals which spawned were collected only a few months before. To my knowledge there has not been any documented spawning of coral which have been in the aquarium for over 12 months. The coral morality problem is severe enough that we are just about to start some proper experiments to determine what it is that the corals don't like (this is where I became invovled). The Aquarium is short-staffed and there has been verly little documentation of what actually happens to corals during their fatal visit to the the aquarium, so the first step will be to quantitatively describe the appearance and physiological responses of the corals once they are introuded into the aquarium. The next satge will be to try various manipulations to improve their health. As basic physical parameters such as salinity, temperature and light are all maintained within known favouralbe limits, the basic working hypothesis is that there is something screwy about the water chemistry. Its even possible that the algal scrubbers are introducing nasty chemical toxins due to the presence of a few undesirable algal species. The manipulations planned are the type of things most aquarists consider essential, but which aren't supposed to be requried with Adey's setup. e.g Activated carbon filtration Protein skimming UV treatment Addition of calcium Removal of algal scrubber system As far as I am aware, Adey's system in the Smithsonian has the same problem as us regarding coral mortality. You can find one or two that survive but most (especially Acroporas) die eventually. The impression I get is that no-one has been able to get a closed circuit aquarium going that truly resemble a real reef in terms of coral health. However I think that some very interesting and productive approaches have been taken by amateur aquarists. I'm open to any suggestions and/or comments. Regards .... Jamie Oliver -- ------------------------------------------------------------------------------- Jamie Oliver Managing Australia's Great Barrier Reef  ## Denitrification Explained- Don't Bother ### by dbs-at-hprnd.rose.hp.com (Dave Sheehy) Date: 10 Mar 1994 Jay Cheroske (cheroske-at-ocf.berkeley.edu) wrote: : Algae remove nutrients : more smoothly and easily than water changes. Unfortunately, algae tend to leak DOCs and nitrogen back into the water. Some algae species leak up to 10% of their biomass back into the water (ref. Spotte). Those DOCs then have to be removed by some other means especially the refractive DOCs. The only way I know of for removing refractive DOCs is water changes or GAC (skimmers don't remove refractive DOCs very well). So, while algae srubbers may have some good points, they most definitely have some pretty serious downsides as well (which require auxilliary filtration to deal with). That's why many of the public aquariums which have been utilizing Adey's methodology have added auxilliary filtration units (like GAC) to their systems. : I know arobic bacteria populations can change rapidly, but : anarobic? Anyone? My references state that it takes 18-21 days to cycle a denitrification filter. That's comparable to rate it takes Nitrosomonas to cycle. : Although Dr Adey recomends MH lights for scrubbers, in practice it's not : required. Indeed, I have read that cool white fluoresents are sufficient lighting for an algae scrubber. Dave Sheehy  ## [M] Scrubber Tank Update ### by laurence-at-cco.caltech.edu (Dustin Lee Laurence) Date: 28 Jan 1994 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).  ## aquaricare algae scrubbers ### by todd-at-mindspring.com (Todd Lovern) Date: Fri, 17 Feb 1995 Newsgroup: alt.aquaria In article <3httm9$2mh-at-ixnews3.ix.netcom.com> selby-at-ix.netcom.com (DAVID KIFFER) writes:
>From: selby-at-ix.netcom.com (DAVID KIFFER)
>Subject: aquaricare algae scrubbers
>Date: 15 Feb 1995 22:02:49 GMT

>I am setting up a new Lake Malawi cichlid tank and had about decided on a
>wet/dry to handle the heavy bioload of a densely populated community display
>tank, instead of my usual canister filtration.  As I am in the market for a
>new filter, I reread the monthly ad in FAMA for MMFI Aquaricare Algae Scrubbers.
>I called and received the literature and a personal call from a rep.  The system
>consists of troughs of algae through which tank water flows and the algae then feed
>directly on the ammonias in the water, removing them completely.  The system is
>represented as more natural than a wet/dry or other bacteria-based system which
>converts the ammonia to less toxic NO2 and ultimately NO3 which has to removed
>by water changes.  Other benefits include zero Nitrogen-based wastes, natural food
>for the fish, less frequent water changes, and increased O2.
>The system is expensive: about $800 (with direct purchase 25% discount) for a >pre-filter, 100 gal tank-rated Algae Scrubber, light system for the Algae Scrubber, >pump, hoses, and hardware. I would supply my own reservoir. For this much money >I could buy a new larger tank and a really good wet/dry system. While I am >principally concerned with optimum water quality, I have no experience with this >company nor their products. >Does anyone have experience with Algae Scrubbers to pass along? Will appreciate any >information available. >Thanks, David For principles of 'algae scrubber' operation, see "Dynamic Aquaria" by Walter Adey & Karen Loveland. Best reference on scrubbers available. In reference to Aquaricare/Marks Marine Fish Scrubbers, I bought one about 9 months ago. It works and is semi well-constructed, but for my next four scrubbers I built them myself and got much more satisfactory results. The mmfi units are poorly engineered and very inefficient. I am an engineer and saw the mistakes they made, and just decided that for 1/4 the cost I could construct my own and get a scientifically and biologically excellent piece of hardware. BTW, in my mind they should only charge us about$40.00 U.S. each for these
units instead of $120.00, they're just an acrylic box with flourescent egg-crating and nylon mesh and Home Depot type fittings with an 2x18Watt flourescent ballast light. Just my opinion, though. As a general rule with scrubbers, they are superior to wet/dry on all of my tanks, but watch them carefully to prevent a takeover of slime algae and about every 5 weeks (at most) clear the culture from the substrate to prevent Nitrate leaks. Also, experiment with setting the algae light timer in opposition to your tank light timer to provide and oxygen boost about 1/4 of the way through the night, especially in heavily planted tanks. T  ## MMFI Aquaricare Algae Scrubbers ### by todd-at-arkenstone.com (Todd Lovern) Date: Fri, 24 Feb 95 Newsgroup: rec.aquaria In article <3i7nce$n1a-at-ixnews2.ix.netcom.com>, selby-at-ix.netcom.com
says...
>
>   I posted this to alt.aquaria, however, received only two responses,
both of w
>hich
>said the system works but can be homemade for around $40. Would appreciate some > >feedback if anyone here has had experience with Algae Scrubbers. > To recap, I am setting up a Malawi community display tank which will be fairl >y >densely populated. >The system sounds too good to be true, in that it is represented as much >more >natural than bacteria-based systems, removes all nitrogenous wastes, reduces the > need >for water changes, gives higher O2 levels, and the algae in the scrubbers can be > >harvested for natural food. > One consideration is price: about$800 for a prefilter, Algae
Scrubber rate
>d for
>a 100 gal tank, lighting system for the Scrubber, pump, hoses, and
hardware.  I
>would
>supply my own reservoir.  This seems awfully expensive.

I have used an MMFI scrubber for some time (1 year), and have following
suggestions:

1) Get a book call "Dynamic Aquaria" by Walter Adey & Karen Loveland ISBN
0-12-043790-2 It has all the info on scrubbers you willneed, and is a
great aquatic biology reference.

2) After I Stupidly plunked down my $220.00 (US), I got the thing: It is an plastic rectangular box with flourescent egg-crating and nylon mesh screen and a Home Depot$15 flourescent ballast (I'm not kidding). I have
Built six more for my other aquaria that perform MUCH MUCH better for
less than I paid for the single MMFI unit. I am Engineer, but Anybody
could do better than this. You would do yourself a favor to make your
own. The MMFI unit is poorly engineered and made of about $45-50 dollars worth of parts, not including engineering/test time, since its apparent they didn't do any :). For a 100 gal tank you could make it for about$80-100 (not including pump).

As for the principle, it works very well, be careful about feeding the
algae back to you fish, since alga incorporate many toxins (metals, trace
elements, etc) into their structure in a concentrated form. The traces of
copper & lead in your pipes will go right back into the tank and
accumulate. I wouldn't totally nix the biofilter, just mount it upstream
(before) the scrubber in your plumbing. This way the CO2 rich water from
the biofilter is exchanged for O2 rich water from the scrubber, back into
the tank. Email me if you need more help.

T



## Building an ALGAL SCRUBBER for marine aquaria...

### by erno-at-mrcnext.cso.uiuc.edu (Erno Pena) Date: Fri, 27 Mar 1992 Newsgroup: rec.aquaria

Algal Scrubber for Marine Aquaria

Sometime this summer, before I build my 75 gallon wooden tank, I plan on
building an algae scrubber for marine aquariums. I've seen quite a few
already, and I know there is much discussion about them in the book _Dynamic
Aquaria. I hope someone out here can offer some advice on my design.

This is my plan: I have an 12 gallon shallow plastic bus tray about 8 inches
deep and 24 inches long. I will mount two bulkheads at opposite sides for
water intake and output. There will be a Tri-Lux or similar plant fluorescent
lamp above. The water will be about 5 inches deep and will be fed by gravity,
which should provide a slow circulation. The water from the overflow box and
prefilter will be split, with some going into the scrubber, and the majority
into the drip plate. The water will travel through the scrubber and out into
the drip plate.

So far this is the easy part. The hard part is making the screen on which the
algae will grow, and actually seeding the scrubber with algae.

I plan to use fiberglass screen formed into a wavy pattern that affords me a
greater surface area. I will take some thick, stiff, plastic coated wire,
form it around the screen into a wide wave with about an inch between crests.
The water will flow down the troughs of the waveform instead of through. I
chose the screen because I've seen pictures of scrubbers using screens, and
because it will also allow water to flow through it, through a wall of algae.

Once the scrubber is built, I'll seed it by going to the local fish store and
asking them to take a small bag and fill it with water and a small bunch of
green hair algae from their reef tanks. I'll take the scrubber, attach hoses
to the in- and outlets and connect them to a small powerhead to circulate the
water, add the starter algae culture to the screen, and let the light grow
the rest. There should be a rather lush growth in a few weeks, by which time
I should have my tank built and cycling.

The only maintenance for this scrubber should be periodically adding
phosphates and removing excess algae. This excess algae can be fed to your
fish, making the scrubber double as a food machine. Other than this, I don't
see much more maintenance required.

Well, that's my plan. I included diagrams below for clarification. I hope it
works. What do you think? Is there anyone out here with experience building
these things? There are a few questions I have however.

- Are there places where I could buy a good, abundant algae starter
culture to speed things up?

- I plan on having only two fluorescent bulb for lighting. Should I get
more?

- I plan on adding some phosphate for additional fertilization for just
this scrubber. Good idea, right?

- Exactly what type of algae should be grown in this scrubber? I forgot
what _Dynamic_Aquaria_ recommends.

- Is there a general size requirement for scrubbers for a given tank
volume? (i.e. would this ~10 gallon algae scrubber be able to support
a 75g tank?)

I can't think of any more. Please email or post your thoughts and criticisms.
I'll post a summary of all the comments.

Thanks.

erno

top view
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|   |   |   |   |   |   |   |   |   |   |   |   |   |   |   |
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--

E r n e s t o   F.   B.   P e n a
---------------------------------
erno-at-uiuc.edu   NeXTmail accepted



## Building an ALGAL SCRUBBER for marine aquaria...

### by (e-mail) (Erik D. Olson) Date: Fri, 27 Mar 1992/1996 Newsgroup: alt.aquaria

In article <1992Mar27.071626.26599-at-ux1.cso.uiuc.edu> erno-at-mrcnext.cso.uiuc.edu (Erno Pena) writes:

>Algal Scrubber for Marine Aquaria

>Sometime this summer, before I build my 75 gallon wooden tank, I plan on
>building an algae scrubber for marine aquariums. I've seen quite a few
>already, and I know there is much discussion about them in the book _Dynamic
>Aquaria. I hope someone out here can offer some advice on my design.

Cool.  Now I know of three people (including myself) who are interested
in this.  I am also planning on building such a beast, though for a fresh-
water tank (this time, at least).

> [plan deleted.  Synopsis:
1a. plant light
2. fiberglass mesh screen around a wire for the turf.
3. trickle filter as well?
4. seeding algae from local fish store.
5. phosphate fertilizer

1. I got the impression from _Dynamic Aquaria_ that the most important
item of the scrubber was the dump bucket allowing the water to surge over
the turf.  You don't want to do this?

1a. The details for light and size is given in a big table in Chapter 12
(I don't have the book in front of me right now, so I don't remember
the page number).  I am going to use those sizes as guidelines.  I think
it was .085m^2 for a 70-gallon tank.  The lighting you suggest may be
way too small.  The prototype in the book uses 4 HO or VHO bulbs (200
watts or so).

2.  I am going to construct my screen like a common windowscreen.  I
think I'll even use some of that plastic windowscreen mesh.  It will be
a plastic grooved frame with some plastic cording that they use for
windows to jam the screening in there.  The tough part here is grooving
the plastic frame, but I have a table saw available.  I suppose if I didn't,
then I could use wood and nails to accomplish it.

3. Why use a trickle filter as well?  I got the impression from the book
that you don't need (or want, for that matter) any filtration on this
system.  Maybe I missed something.

4 & 5. Dunno.  Was a little hazy on aspects of seeding and fertilizer.

Be sure to post your progress on this!  Also Todd OBrien (tobrien-at-macalstr.
edu) worked for Dr. Adey's group at the smithsonian and knows firsthand all
about these... might want to talk to him.

Erik Olson
---
Erik D. Olson				(e-mail)
University of Washington		     (e-mail)
Cosmic Ray Labaratory



## Building an ALGAL SCRUBBER for marine aquaria...

### by patti-at-hosehead.intel.com (Patti Beadles) Date: Sat, 28 Mar 1992 Newsgroup: alt.aquaria

FWIW, _Dynamic Aquaria_ is a book that is frequently criticized by many
knowledgable folks who have read it.  I've also heard severe criticisms
of the Smithsonian aquarium that is run with only algae scrubbers.

You will need a relatively large activated carbon filter to deal with
the byproducts of the algae.  This will need to be changed frequently.
--
patti-at-hosehead.hf.intel.com | I don't speak for Intel, nor vice-versa.
75555.767-at-compuserve.com |
(503)-696-4358 | A1: Yes, I'm the one with the big fishtank.
or just yell, "Hey, Patti!" | A2: A lot, a lot, yes you can see it sometime.



## Algae Scrubber filters

### by David Aiken <d.aiken/eis.net.au> Date: Mon, 22 Sep 97

On 22/9/97 12:38 AM, IDMiamiBob-at-aol.com IDMiamiBob-at-aol.com wrote:

>    I am thinking of trying an algae scrubber filter in my 30 gallon tank.
>nitrates.  The algae part particularly interests me.
(snip)
>    My question is this:  will this "miracle filter" compete with the plants
>in my tank? Will it overpower the available supply of micronutrients?

Yes, the miracle filter will compete - plants and algae are both plants
(sorry about how that sounds but you know what I mean).

You _can_ get the same results as an algae scrubber produces by keeping
plants _in_ your tank - those green things you're trying to grow do the
same things for water quality as algae, and look a lot prettier! Some
plants are better than others at achieving the same "scrubbing" effect as
the algae. The other issue is quantity and the standard recommendation
for a "heavily planted tank" comes to mind.

While algae scrubbers can be very effective, so can plants. If I was
going to run a scrubber, I'd steal a hint from Adey and Loveland's
"Dynamic Aquaria" and try running it on a reverse light cycle (light the
scrubber while the tank is unlit and vice-versa). Effectively this means
that you always have some photosynthesis (hence oxygenation) going on.

I have no idea how effective this would be, and no real desire to try it
- - I'm finding the plants do a good enough filtration job on their own
without the need for extra plumbing and equipment. Having thrown the idea
out, however, I did get the idea of setting up a second plant tank - a
"plant scrubber" - connected to the first tank but in a different room,
and running it on a reverse lighting cycle. Just think - 24 hr plant tank
viewing options (g)!!!

Basically, though, I think that an algae scrubber is unnecessary in a
well planted tank and could cause nutrient shortages for the plants. I
also wonder how you keep the algae from spreading from the scrubber to
the tank. I think it would be much more appropriate, and more effective,
on a fish only tank, or a very lightly planted tank where you don't have
to worry about competition for nutrients.

The other place where it could be effective would be in (as, actually) a
tank designed specifically for algae eaters - loricariid catfish or some
rift lake cichlids. If you could get the right algae growing in
sufficient quantity in the tank but not on the glass, you could turn an
algae scrubber into a display tank. I've never really seen a tank
deliberately designed to maximise algae in that way. It could prove quite
an interesting planted tank in its own right.

David Aiken



## Reverse photoperiod filtration?

### by "Roger S. Miller" <rgrmill/rt66.com> Date: Sat, 15 Apr 2000

On Sat, 15 Apr 2000, Tom Barr wrote:

> Do algae use N at night also like the bacteria and plants? To what extent?
> If they do, what the heck is this notion of Reverse Photo period for
> filtration? If the nitrogen is being used up by both the plants and the
> bacteria and maybe algae then why do these companies promote the Reverse
> photo period idea as being an some sort of advantage when using
> scrubbers/filters for N removal?

The most authoritative reference I know of for reverse-cycle filters is
"Dynamic Aquaria" by Adey and Lovejoy.  Their content is a little
questionable as far as I'm concerned because they're pretty much
advertising for the Algae Turf Scrubber (R) system.  Just the same, what
they say (p. 234) is "While the microcosm is in darkness, the algae in the
scrubber are photosynthesizing, insuring a continual supply of oxygenated
water, and rapidly removing CO2 and nitrogenous waste just when it is most
abundant."

I can see their argument for evening out the oxygen supply with
reverse-cycle lighting.  This would also even out the CO2 demand and
smooth out any pH swing.  I'm unclear on the link to nitrogen uptake.

Raven, in "Energetics and Transport in Aquatic Plants" pointed out that
respiratory processes in aquatic plants (mostly he was talking about
algae, but the basic mechanics are the same for plants) are suppressed by
as much as 95% during during the lighted period.  That is so the plant's
resources (ATP supply, for instance) can be focused on photosynthesis. I
doubt that the suppression of respiration will happen in roots or any
other non-photsynthetic tissue.  Plants use respiraton to get the energy
they use to reduce nitrate to ammonia; they also use molecules produced
during respiration to build the proteins that would use nitrogen.  So if
anything, it appears to me that nitrogen uptake by plants and algae should
be *suppressed* when the lights are on.

Uptake and use of nitrate specifically might be a little different.  I
read recently that plants can divert NADPH produced in the light reactions
of photosynthesis to reduce nitrate to ammonia.  This reduction would
occur only in photosynthetic tissue and only when the lights are on.
Also, nitrate is only one source of nitrogen.

I can see why the reverse lighting cycle is a good thing for the oxygen
supply and for evening out pH swings.  But when it comes to any advantage
in nitrogen uptake, all I can say to its proponents is "prove it".

Roger Miller



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