Atlantic Biofall FilterIN STORE PURCHASE ONLY, ITEM CANNOT BE SHIPPED Biological filters remove suspended solids, convert toxic ammonia and nitrites to harmless nitrates and aerate the pond Atlantic's FilterFalls are designed to be able to expand filter capacity as ponds age and fish grow Efficient removal of toxins and floating particles from the water column improves water quality and clarity Oversized chamber contains more media material to start with, accepts additional