biodegradable balls live bacteria slowly released Pure Pond is our Award Winning bacterial product that helps to maintain crystal clear and healthy pond water PURE POND are biodegradable balls crammed full of live bacteria and enzymes that when added to your pond filter. The bacteria and enzymes are slowly released when they are needed most to address biological issues in the pond that are often the cause of poor clarity. PURE POND balls work particularly well within the Nexus filtration system. Simply add the balls into you biological chamber ideally held within a filter bag where they will agitate alongside the K1 Media. When using PURE POND balls as a maintenance product, the balls will help to maintain crystal clear and healthy water.