These biodegradable polymers provide a time-released source of food for bacteria that assimilate nitrate and phosphate. As bacteria develop, excess growth sloughs off due to water movement from the filter, allowing these bacteria to be removed with a protein skimmer or used as planktonic food for corals, clams, and sponges. Best installed in fluidized filters, Bioplastics can also be placed in a regular filter media bag inside your filter to decrease nitrate and phosphate levels.