how much food is over feeding?

[Myka]

Originally Posted by Aquattro

The question is more about getting the nutrients out rather than adding them.

This is a good point. It doesn't sound like you're overfeeding, but you somehow have a nutrient sink.

Poor flow is another concern; if waste is allowed to settle in the tank rather than getting flushed down to the sump (or flushed into an HOB filter or skimmer) it will break down within the tank and cause nutrient issues.