Hydor Professional External Canister Filter Media， Zeolite</br></br><div style="text-align:left"><b>[Product Information]</b><br><ul><li>For Use With Any Size Hydro Professional Canister Filter; Can Also Be Used With Other Canister-Style Filters</li><li>Box Contains 550Gm Pouch</li><li>Chemical Filtration for Freshwater Aquariums， specifically for removing ammonia， dyes and drug residues from aquarium water</li><li>Zeolite Should Be Used As A Middle Stage Of Filtration</li><li>It Is Recommended That Zeolite Should Be Changed Out Every 1 To 3 Months</li></ul></div></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br></br><img src='http://ecx.images-amazon.com/images/I/51zl%2BQHIW%2BL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/51Pt-xc7beL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41pDYJ3SW1L.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/41zc3Dj667L.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/31xn0QAEOCL.jpg' noproxy></br><img src='http://ecx.images-amazon.com/images/I/01OKn5uVjpS.png' noproxy></br>