I used this one for 3 years then sold the tank and ordered another for my recent 220gal, works perfectly for pellets, never used it for flakes, but I'm sure it would do the same. The opening setting for the pellets is very small and can go much larger to use flakes, batteries last years I can run pellets dropping a small amount at 10am it waits a minute and drops the same amount again, then at 2pm same cycle, has over 6 setting durations either 1 drop or two for each. Basically you can schedule pretty much how often and how much you want daily. With those settings the food last approx 3 weeks.
http://www.ebay.com/itm/Digital-LCD-...item27d25e6d64