Natural Chemistry Phosfree, 3 L, 4 Pack, Phosphate Remover, Quick and Easy to Use, Improves Filter Performance, Reduces Pool MaintenanceBrand: Natural Chemistry Features: Reduces Phosphates: Natural Chemistry's Phosfree enables pool owners to drop phosphate levels in your pool to almost nothing. Clear Water: PHOSfree works in the filter to minimize any water clouding, ensuring the water stays sparkling clear. No Phosphates, No Problem: PHOSfree is formulated from lanthanum (rare earth) compounds. When added to your skimmer, a thin coating of PHOSfree forms on the filter media. As pool