Maintaining an outdoor pond is quite different to an indoor aquarium. There are many variables outside; weather, various birds and animals, and difficulties for some to adequately filter their water. Even ongoing, general maintenance on a large pond can be a challenge. Tap water contains Chlorine and Chloramines which kill bacteria, and while tap water is safe for human consumption these chemicals are toxic to fish. Blue Planet Pond Vital instantly neutralises Chlorine and will break the chloramines chemical bonds, making tap water safe for fish. At the same time essential electrolytes are added to ensure fish remain healthy. Use Blue Planet Pond Active at the same time to ensure a healthy ecosystem is maintained. In cases where you have excessive leaves or debris entering the pond, Blue Planet Sludge Buster is recommended.