I have a feeder for my 20 gallon office community tank. It works no problems, feeding the fish friday-sunday every week, more if I take vacation days. I got one with 14 different food compartments. It can be set up to feed 1-4 times per day. I have it feeding 2x per day, so the 14 compartments last 1 week. It can't overfeed, because I fill each compartment with the right amount of food. flakes in the day, and a bit of algae wafer at night for my BN plec. The only problem I have is when the battery dies, but I don't really care when that happens, since I find out within 3 days tops. If I think the battery is low and am on vacation for more than a week, I put in a new one.