Big Al's Multi-Purpose Bio-Clean reduces the time and need for cleaning power filters, gravel and interior aquarium surfaces. An organic waste digester, Bio-Clean will dissolve sludge in your aquarium caused by fish waste, over-feeding and other decaying matter. Bio-Clean is heavily concentrated with live, highly active bacteria and enzymes which go to work instantly. Bio-Clean may cause ammonia levels to spike. Big Al's Multi Purpose Bio-Support supplement can be used to control ammonia and nitrite spikes. Together Bio-Clean and Bio-Support make the ultimate maintenance team.