Guppy Fry Questions,

[TheSims3Dude]

Question, why does my tank smell really bad? I clean the gravel in the tank at least 4-5 times a week, I have a filter (it's for 5-20 gallon tanks)
I change the carbon, once a month, the foam, every 2 months, and the white chalky stuff (dunno what it's called, lol) every 3 months. That's what it says to do on the boxes for these, so I can't seem to figure out why my tanks smells, and not a good smell either, lol
What can I do? I feed my fish at least 4-6 times a day, but like I said earlier in the thread, I clean the tank 4-5 times a week,.. (50% change) and gravel vac/clean (whatever it's called) it too,...

EDIT:
I just cleaned the tank and it smells better, is it 'cause the ammount of food? Should I just be putting a pinch in? (there's 3 mollies and 4 guppies)

 

[OldMan47]

3 mollies and 4 guppies will eat almost nothing. It sounds like you may have correctly diagnosed the problem. Rotting food is a real nasty smell in a tank.

 

[TheSims3Dude]

Oh! I cleaned the tank out and only put a pinch of food in, and it seems to be working a lot better!
it finally doesn't have a gross smell in my tank! lol