I have a 2.5g and everyone told me that it would be hard to keep the water quality decent. I have had no problems with it at all. I was testing every day, and everything stayed the same, so I have lengthened the time between testings so that I am now testing when I top off the tank, every 3 or 4 days. I have a cleaner shrimp, a scarlet hermit, a cerith snail, and 2 other unidentified hermits in there, with about 2 lbs of LR, and about 3 lbs of LS.