I do weekly 10 percent water changes and use real ocean water. I usually cut new filter floss every couple weeks, looks like its about that time. I didnt cut the entire wall, just widened it about an inch. In chamber 1 I just have the stock filter pad which I gutted out and used to hold floss. in chamber 2 I have floss, then carbon, then live rock and the skimmer. I put the skimmer in first, then dropped the live rock beside it. The hood fits perfectly and theirs no visible signs of any cuts when the tops down.