Phosphate remover provides efficient removal or lowering of phosphate levels. Chloride based formula. 1 Qt. removes 1000 ppb (parts per billion) of orthophospate out of 20,000 Gal. of pool water. Removing orthophosphate is less expensive than fighting persistent algae growth. Does not contribute to scale formation. Filtration system will remove the precipitate to be backwashed to waste, so there is no need to vacuum.