I used a bunch of them when I was maintaining off site tanks for the pet store I used to manage. they were ok for shrimp pellets. but not great for flake food. I cant remember the name brand though. I'm sure they were the cheapest ones on the market my boss was a scroodge. the biggest problem I noticed was like mechanical timers they lost between five and ten minutes a day so eventually they were dropping in food when all the fish were asleep. I removed them from all the marine tanks and just left them on fresh water tanks,.