I have posted this several times before, but for new members here is a simple, cheap way to replace your filter media. They media you can buy from the store gets expensive and usually comes with carbon that you don't need to use - unless you need to remove meds from the tank. I buy quilt batting from the craft section of nooppee and cut it to size, I fold it over the inserts and bingo - clean and cheap! They seem to need replaced every week, but I see that as it is getting lots of stuff out of the tank. I have done this for at least 6 months with no problems at all. And one roll lasts for a long time!