Mega Powerful Nitrate and Phosphate Remover - DIY!

SantaMonica

Plecostomus
MFK Member
Oct 9, 2008
680
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Santa Monica, CA, USA
Great Barrier Reef Aquarium

Many people who have not built a scrubber properly (after August 1988) often say how the Great Barrier Reef aquarium was a scrubber "failure" because the corals did poorly. Apparently these people have not done much reading. In the early days of that aquarium, the scrubber was doing it's job great:

1988:

Nutrient Cycling In The Great Barrier Reef Aquarium
http://www.reefbase.org/download/download.aspx?type=10&docid=10506

"The Reef Tank represents the first application of algal scrubber technology to large volume aquarium systems. Aquaria using conventional water purification methods (e.g. bacterial filters) generally have nutrient levels in parts per million, while algal scrubbers have maintained parts per billion concentrations [much lower], despite heavy biological loading in the Reef Tank. The success of the algal scrubbers in maintaining suitable water quality for a coral reef was demonstrated in the observed spawning of scleractinian corals and many other tank inhabitants."

But did you know that they did not add calcium? That's right, in 1988 they did not know that calcium needed to be added to a reef tank. Even five years after that, the Pittsburgh Zoo was just starting to test a "mesocosm" scrubber reef tank to see if calcium levels would drop:

1993:

An Introduction to the Biogeochemical Cycling of Calcium and Substitutive Strontium in Living Coral Reef Mesocosms
http://onlinelibrary.wiley.com/doi/10.1002/zoo.1430120505/abstract

"It was hypothesized that Ca2+ and the substitutive elements Sr2+ and Mg2+ might [!] have reduced concentrations in a coral reef microcosm due to continuous reuse of the same seawater as a consequence of the recycling process inherent in the coral reef mesocosm."

"The scleractinians (Montastrea, Madracis, Porites, Diploria, and Acropora) and calcareous alga (Halimeda and others) present in the coral reef mesocosm are the most likely organisms responsible for the significant reduction in concentration of the Ca2+ and Sr2+ cations."

"Ca is not normally a biolimiting element, and strontium is never a biolimiting element; HCO3 [alk] can be. It appears that, because of a minor [!] limitation in the design parameters of the mesocosm, these elements and compounds may have become limiting factors. [...] It is surprising that the organisms could deplete the thousands of gallons of seawater (three to six thousand) of these elements even within two or more years [!!].

"The calcification processes are little understood."

So then in the late 90's, the Barrier Reef aquarium start using up it's supply of calcium, and the folks there said "the corals grew poorly". Really. No calcium, and the corals grew poorly. So they "removed the scrubbers" and "experimented with the addition of calcium" sometime after 1998. Then in 2004 it "definitely improved a lot". Really.
 

Weylin

Blue Tier VIP
MFK Member
Sep 15, 2007
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Inside a Bottle
I'm still having phosphate problems in my tank.. here are the details..

Tank Size: Aprox 22-24 gallons

Screen Size: 6x4" Lit on Both Sides

Lighting: 2x CFL 15watts - 2700k. Lighting is on for aprox 12-15hours daily.

Cleaning: Once a week.


I think its the lighting period, i might have to increase it.. ?
 

SantaMonica

Plecostomus
MFK Member
Oct 9, 2008
680
53
61
Santa Monica, CA, USA
Low-light Scrubbers

Here is something new, different, and untested. I have not built one yet, but it should work for either SW or FW if the size and flow are correct. It is a vertical scrubber that you hang on the wall, and it requires NO electricity. It is a "low-light" scrubber:






I got the idea when reading a study about algae growth in freshwater streams:

"Algal Response to Nutrient Enrichment In Forested Oligotrophic Streams". Journal of Phycology, June 2008. http://www3.interscience.wiley.com/journal/120083425/abstract

"Algae inhabiting forested streams have the capacity to acclimate to low light intensity. These light conditions affect their photosynthetic efficiency, but do not impair growth rates, in particular, in the case of thin diatom-dominated communities."

In other words, they don't filter as much per square inch (or per square cm) of area, but they do operate on very low light. Apparently it is mostly diatoms that grow in these low-light conditions.

The advantage of a scrubber like this should be obvious: It requires no electricity to power the screen. It still requires a pump, however, since the top of the scrubber would (probably) be high above the top of the tank. The scrubber is designed to operate on the light already available in the room, which would vary greatly depending on how strong the light bulbs are in the room, and how much sunlight comes in through the windows. The more average light the room has, the smaller the scrubber can be. The less light, the bigger it needs to be. Basically, the scrubber uses more area to make up for less light. And since the light is so low, the type of algae that is able to survive is (apparently) mostly diatoms.

Just as with regular scrubbers, the wider the unit it, the more flow is required. So in the spirit of keeping it from consuming too much electricty, a smaller pump could be used if the unit were narrow and tall. But the bottom of the unit will need to drain into either the tank or the sump, so there will be a limit to how low the bottom can be. And the limit to the top will be the ceiling. A tradeoff will need to be made, maybe so that it looks like a vertical picture on the wall. Fortunately the flow does not need to be as much as a regular scrubber, since it is one-sided only.

It will have to be experimented with to see if a clear cover is needed to stop any water dropletts from splashing out. Many people have decorative waterfalls of the same size as these, and they have no cover on them, so maybe water dropletts getting on the floor will not happen. Evaporation would be high though, and this might be reason enough to consider a clear cover.

Cleaning could (apparently) be done by having a removeable screen or porous sheet, just like a regular scrubber has. It would be big though, and would drip as you took it out. Also it probably would not fit into a sink, and so would need a bathtub or shower (or outside) for cleaning. A possible fix for this might be a very flexibe woven plastic mesh, which you could fold up like a towell and easily clean in a sink. A material like this might not lay down flat when it's in the scrubber, however.

This type of scrubber would be easiest to try for somebody with a cement floor, lots of wall space, open widows or skylights, a low sump, high ceilings, and a big sink or patio for cleaning. I have no idea of the size required for the unit.
 

Tien

Feeder Fish
MFK Member
May 1, 2010
198
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Las Vegas
Holy cow...I have been reading for some time and only have read through the first 15 pages of this thread! I plan on reading the entire thing and trying this myself. I am way hyped about it.
 
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