Phosphate and the Reef Aquarium

[Boomer]

http://reefkeeping.com/issues/2006-09/rhf/index.php

[HowardW]

Excellent article, thanks!

[boozeman]

food for thought

[Woodstock]

I have a project underway in which I am comparing the relative efficacy of phosphate binders in seawater, and I hope to publish the results in future articles. Unfortunately, such comparisons are very time consuming, as it can take many days for the media to reach equilibrium (that is, to finish binding or releasing phosphate) in phosphate-containing seawater, and so to do these tests for a large number of different phosphate concentrations (the way that scientists compare phosphate binding materials in terms of potency) can take weeks to months.

I REALLY want to read his findings!!

Summary of Phosphate Reduction Methods
My suggestion is for aquarists to target a phosphate concentration of 0.02 ppm phosphate, or less. Here is a list of ways that many aquarists export phosphorus and maintain appropriate phosphate levels. They are listed in order of my preference for addressing these issues in my own system:
1. One big winner is macroalgae growth. Not only does it do a good job of reducing phosphate levels, but it reduces other nutrients (e.g., nitrogen compounds) as well. It is also inexpensive and may benefit the aquarium in other ways, such as being a haven for the growth of small life forms that help feed and diversify the aquarium. It is also fun to watch. I'd also include in this category the growth of any organism that you routinely harvest, whether corals (e.g., Xenia sp.) or other photosynthetic organisms.
2. Skimming is another big winner, in my opinion. Not only does it export organic forms of phosphate, reducing the potential for them to break down into inorganic phosphate, but it reduces other nutrients and increases gas exchange. Gas exchange is an issue that many aquarists don't ordinarily recognize, but it is the primary driver of reef aquarium pH problems.
3. The use of limewater, and possibly other high pH alkalinity supplements, is also a good choice. It can be very inexpensive, and it solves two other big issues for reefkeepers: maintaining calcium and alkalinity. Simply keeping the pH high in a reef aquarium (8.4) may help prevent phosphate that binds to rock and sand from re-entering the water column. Allowing the pH to drop into the 7s, especially if it drops low enough to dissolve some of the aragonite, may serve to deliver phosphate to the water column. In such systems (typically those with carbon dioxide reactors), raising the pH may help.
4. Commercial phosphate binding agents clearly are effective. They can be expensive and may have other drawbacks, but can drive inorganic phosphate to very low levels, if that is a goal.
5. Driving bacterial growth is another option. Not only does it do a good job of reducing phosphate levels, it reduces other nutrients as well (e.g., nitrogen compounds). It is also very inexpensive and may benefit the aquarium in other ways, such as providing a food source for certain organisms. Its drawbacks are that it makes it difficult not to drive the nutrient levels too low, and the fact that it consumes oxygen as the bacteria use the added organics as a carbon source.

EXCELLENT information~

[boozeman]

how about zeolithic media for phosphate removal?
also boomer, do you recomend the dosing of alchohol or sugar as a means of accelerating a bacterial bloom for expediting nutrient removal ?

[boozeman]

?

[Boomer]

how about zeolithic media for phosphate removal?

Never heard of any. What media are you referring to ? Any zeolite in seawater would be terrible at removing PO4.

also boomer, do you recomend the dosing of alchohol or sugar as a means of accelerating a bacterial bloom for expediting nutrient removal ?

I don' but that is me There are lots of people that do use it. The thing with sugar is it sucks up O2. I'm not into this voka, sugar or alcohol thing at all, so I can't reaaly help you. On the chem forum on RC there are lots of threads on it. Now there is an active thread on sugar.

[BoomerD]

Can you decipher that "chemistry geek-speak" into something us dummies can understand?
While I know that phosphates are a problem in our tanks, and are something that comes from almost everything we put in the tank, controlling them becomes problematic for most of us.
I finally learned to soak & rinse all frozen foods in RO/DI water to help remove the phosphates added in the processing, and I know that most flake foods are EXTREMELY high in phosphates, (difficult to soak in RO/DI), but we GOTTA feed the critters we keep...

[Boomer]

What would you like me to try to explain to yah-there evil twin

No questions on sugar, alcohol or vodka.

Soak/rinse food ? I too use to, especially brine shrimp

[boozeman]

I meant as a nutrient export..when the zeolithic pores become clogged with bacterial growth and then removed/swapped for fresh media.

[Boomer]

Ok you mean in a ZEOvit System

[Woodstock]

I've noticed an increase of green film algae on the glass since I started feeding Omega One Super Veggie flakes(my fish love it) 3 weeks ago I used to have to wipe the glass once every 4-5 days; now I have to wipe it every 1-2 days!

[lgerold]

Summary of Phosphate Reduction Methods
My suggestion is for aquarists to target a phosphate concentration of 0.02 ppm phosphate, or less. Here is a list of ways that many aquarists export phosphorus and maintain appropriate phosphate levels.

I'm confused about the math. I use the LaMotte phosphate test. The lowest reading given is .10 ppm. How can you test for levels below that?

Lucy

[Boomer]

Looks like you are fueling the tank there Donia

Lucy, you bought the wrong LaMotte test kit You needed Model NVM, Order Code 7146. That at least goes to 0.05 ppm. There are other kits that go to .01 ppm or .02 ppm but not LaMotte.

[lgerold]

Boomer, it looks like I'll have to go shopping again!

Thanks!

Lucy