Biological clarifier specially designed for PROBLEM PONDS. Works at top and bottom of pond.Clarifies around rocks and surfaces. Completely safe for all fish, wildlife, and decorative aquatic plants. Eliminates odors, digests sludge. 100% live bacteria-not chemical. Non-toxic, non-pathenogenic. Bottle treats 4800 gals. ( 1 oz per 150 gals.)Shake well before using.