Clears Cloudy water Works rapidly Safe & natural No matter how good your filtration system, your aquarium may be bothered by minute particles which find their way through even the finest filter media. It spoils the look of your aquarium, stunts plant growth by filtering out light and irritates fish gill membranes leading to poorly fish. Pour in Quick Clear and see the effect almost instantly. It clumps fine particles together meaing the filter can grab onto them. The result? Crystal clear aquarium water.