I have the seaclone 100 running on my 20gal. long for about six months now. Its working great. Have to empty the cup every other day. When first set up open the air intake fully and let it run. Don't mess with it. It takes about 4 days to a full week to break in. Mine is still set wide open and the cylinder stays full of very fine bubbles. Cup fills like I said about every other day and the stuff is really dark green to brown. Take the sponge off about once a week , rinse in plain water and replace. That is all I've done so far. Any time now I'll be taking mine apart and clean everything.(six months old) Working great, no problems. The trick is don't play around with it and it will work!!