can someone please tell me what I'm doing wrong?

[Madreefer]

I had a buddy fight this for a year and a half. He tried everything and nothin worked other than cooking his rocks. For months. Just put it in buckets and changed out the water on a regular basis. It sucks I know, but if your setting up a bigger tank it's easier to try and battle it now rather than later in a bigger tank. His started out to with a crapped out skimmer and lack of maintenance.