Helps accelerate the decomposition of leaves, scum, sediment and other organic matter in the fall and winter. Jump start your pond to a healthier environment in the spring. Helps to maintain a healthy immune system for your fish during the winter months; Reduces buildup of dead leaves and organic sediment all winter long; Two part system: 1 quart liquid bacteria and 2 two ounce water soluble packets of cellulose producing bacteria. Continues to provide biological activity in water temperatures under 55 degrees. If frozen, the bacteria will remain effective after thawing out; effective in darker conditions (under ice and snow) Continues to provide sustained biological activity even in water temperatures down to 40 F degrees.