[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~