EcoSystems AquaClearer Extreme Cold Water Liquid Bacteria is scientifically blended and tested to produce maximum results during colder temperatures. During the spring and autumn seasons there is extreme nutrient loading in the pond as trees and plants in and around the pond are dropping organic material, such as flower petals, seeds, leaves, dead branches, etc. AquaClearer Extreme Cold Water contains a proprietary blend of microbes that are effective at accelerating the digestion of this organic material at the bottom of the pond. AquaClearer Extreme Cold Water Liquid is also excellent at reducing ammonia, nitrites and excess nutrients that would otherwise cause poor water quality and clarity.