Kent Pro Clear Freshwater is a long chain polymer which attracts dirt and cloudiness-causing particles into clumps which are easy to filter out or will settle to the bottom of the aquarium. Unlike competing products, Kent Pro•Clear is very safe for all species of freshwater fish, and safe for plants, as well. For best results, use a fine filter floss or pad filter and force water through it. Dirt a nd cloudin ess- causing particles will collect on this filter and can be discarded. If the tank is extremely cloudy, you can double the dose. Do not use more than two doses per week.