very much over feeding, if your fish aren't eating it all.
if you drop those cubes in your tank you are also introducing a ton of phosphates.
how dirty are your bioballs? if there's nothing on them, don't bother cleaning them. how deep is your sand?
i ddon't like the feeding on every third day, but some people do it. I drop some food in the morning, some in the night, but only enough to have them eat it all. every 2 or 3 days my tank gets some good luvin cause i feed my sun coral in the tank and everyone gets extras.