i will have to say my 2 marineland bio-wheels 330 model are the best iv only had them 2 years but within that time i have never had a problem with them and over time its like the filter becomes the best at its job i mean my water is even cleaner than well ever, haha but i never replaced the media i only have put one in sense i got it and i do 4 month water changes somtimes when the tank is looking a little dirty i will do a 5 gallon water change and place a bag of carbon in the filter so im very happy with this filter and i know other people say they arnt good filter but like a new aquarium they need the same thing time and i waited and im getting realy good results.