I am running a rena xp3 on my 20gal. long, I keep foam pad in bottom, bag of chemipure elite also in bottom, middle basket gfo
, top basket full of filter floss to catch fines missed elsewhere. I do water changes 2 times per week and on the 2nd change of the week everything in the canister gets rinsed off in water that I have taken out of the tank. Seems to workout great.