The Carbolit Reactor is a compact chemical filtration chamber for aquarium use. It can be installed in-line with any standard canister filter or used with a seperate pump. The Carbolit Reactor contains one litre of pH nuetral Carbolit. The Carbolit Reactor can be used for fresh and salt water aquaria. One filling lasts, depending on the desired use, between 10 days (removal of medications) or up to 12 months (long-term use as biological filter) in a 100 gallon aquarium. Dimensions - total length is 14 inches and the diameter is 3.2 inches.