PR-10,000 is the strongest, most concentrated phosphate control product available in the aquatics market. It is formulated to react with phosphates in the water, allowing for them to be removed from the solution. It is an all-natural, rare earth phosphate removal product. It reacts with orthophosphates on contact, crystalizing them. The inert phosphates then sink out of the solution to be vacuumed or filtered out. PR-10,000 causes cloudiness in the water for up to two days. Use only as needed.Because of its concentration, a little goes a long way. A dose of PR-10,000 may be surprisingly small to you, but watch it work.