Pond sludge is a build-up of several organic materials such as plants/leaves that fall into the pond water, fish waste, dead algae and dirt, as well as inorganic matter like uneaten fish food. If too much sludge forms it can reduce the oxygen in your water, causing issues for your fish. It can be eliminated by using our pond sludge treatment. 

See our blog post on removing pond sludge to find out more.