Do you have a link to the ceramic rings? How much do I need to fill on AC110?Both of my Fluval 406's have ceramic rings in them as does my 3 AC-110's and one of my Sun Sun HW-303B filters. My other 2 Sun Sun HW-303B's have Seachem Matrix in them. With regular maintenance all of my tanks are sparkling clean and the parameters are right where they're supposed to be.