Fresha Tank is a Microbial product which is placed in a fish tank or waterbutt, the microbial disk uses the same industrial silver as found in drinking water purifiers, hot tub filters and many medical items used for burns victims. The strong microbial action of the 99.9% pure industrial silver destroys fungal, viral, bacterial micro-organisms and parasites in the reproductive stage, this keeps fish healthier, prevents the spread of disease, reduces nitrates and bacteria levels. Just place the disc in your aquarium or waterbutt and it will immediately begin it's work. Ammonia levels are reduced along with phosphates and nitrates due to the reduced levels of bacteria in the water, however Freshatank does not replace the need for usual regular maintenance.