Pond starter bacteria is made with Lithotrophic bacteria that is used in reducing liquid waste and or (cycling the pond). In the spring using heterotrophic bacteria can be dangerous if Lithotrophic bacteria is not present in large numbers. Lithotrophic bacteria also grows very slowly and therefore has difficulty catching up with decomposition caused by the heterotrophic bacteria often causing ammonia problems. When starting a new pond there is nothing for heterotrophic bacteria to decompose and therefore Lithotrophic bacteria is the most important. Pond starter bacteria is ideal for starting new ponds or after winter. We recommend pond starter bacteria for water temperatures of 50°F or above. Coldwater bacteria is a mix of 80% heterotrophic and 20% Lithotrophic bacteria ideal for balancing the pond during winter months or cold water temperatures. Coldwater bacteria should be used as a maintenance product during colder water temperatures. Our new Coldwater bacteria can be used in water temperatures of 40°F or above without any issues.