PR-10,000 is a highly concentrated rare-earth phosphate remover. It is formulated to react with phosphates in the water, allowing them to be removed from solution. It reacts with all known types of phosphates on contact and hardens them into a fine precipitate, which falls out of solution. The inert phosphates then floc out, to be vacuumed or filtered out of the pool. PR-10,000 causes cloudiness, which can last anywhere from a few hours to a few days. Use as needed, and do not exceed the recommended dosage unless otherwise specified. Because of PR-10,000's concentration, a little goes a long way. A dose of PR-10,000 may be surprisingly small to you, but watch it work. PR-10,000 is one of the original Orenda Products and is professional grade.