Brightwell Aquatics Phosphate E liquid phosphate remover begins to eliminate reactive phosphate immediately upon addition to aquarium. Phosphate E is safe for all inhabitants of reef and marine fish-only aquariums. Each ml eliminates 1 ppm phosphate in 4 gallons of water (250 ml treats 1,000 US-gallons). It also helps facilitate the removal of phosphate from aquariums during periods when dissolved organic material is abundant. It may be used on an ongoing basis to help control phosphate in heavily-stocked aquariums. Over 50% stronger than most competing products.