The most efficient and effective way to keep your pond crystal clear is by using a biological filter, a.k.a. Bio-Fall. These units are designed to be hidden at the top of a waterfall or buried at the ponds edge. Water is pushed up from the bottom of the Bio-fall box and up through lava rock, which has tremendous surface area for beneficial bacteria to colonize. These bacteria consume and break down excess nutrients from fish waste and other organic material. With out these beneficial bacteria the nutrients would be left to be consumed by Algae, which is the cause for the dreaded "Pea Soup" look in a pond. Additional nutrient removal can be accomplished by planting an aquatic plant into the top of the lava rock, forcing the water through the roots of a plant, which will consume the same nutrients the algae would like to have.