Instructions for use: Simply fill the SR Aquaristik filter media bags up with your favorite filter media, use the convenient drawstring and spring-loaded closer to secure the media in the bag. Rinse bag thoroughly to remove dust from filter media. Ideal for use with a variety of chemical filter media’s including carbon, zeolite or ammonia remover, iron exchange resin and GFO (granular ferric oxide). Ideal for use with canister filters; clip on filters or in filter sumps.