If you could boil your code down to a dozen (give or take a few) lines that replicate the memory leak issue, and you posted that code here, we might have a prayer of helping you find the problem. Resolving the efficiency issues of tight loops is not relevant to memory leak problems. If you've got a memory leak, the loop is only the mechanism of magnifying it, not the cause of the leak itself. Remember that memory efficiency is completely different than memory leaks. Which one is it?

Why not post your code so we don't have to guess? Often when trimming it down to an "example" version that you can post here, you'll discover the issue on your own, but if not, at least we'll have something to start with.