I've been adding a product called Db200 which has seemed to help quite a bit. So if my math is right take 15 feet width x 350 linear feet around the pond which is 5250 sqft. At a rate of 1 pound per square foot that's 5250 pounds of bentonite ..holy cow! And really I should go 2-4 per foot. What cheapest source found for bentonite? And how much is application of soil floc for an area my size? Thanks guys!