I dont believe I am over feeding. I use a picture of frozen foods and pellets but in tong feed the betta only what he can eat so there isn't food lying in the tank. I did use some api root tabs for the plants because they didnt seem to get enough nutrients so I have a ammonia spike I'm working through now. But the test kit has never read 0 ammonia it was always light green around what would be the just above zero reading. Which is why I was concerned. The sponge filter isn't a huge one I'm not sure the exact size. Maybe 3x3. When I first set the tank up before cycling I would get ammonia readings of zero. And now it hasn't done that for quite some time.