I have various canister filters and the manuals for the ancient Fluvals have me put the sponge at the top. The ECCO has the sponge on the bottom. Does it really matter where they go? I have three ECCOs, two old Fluvals and two Eheim Pros. I don't think any one has an identical configuration as any other one. Does it matter? Will a certain order in media prevent premature clogging? What order of media is your favorite?