Adam,

It sounds like you have found an answer to your problem, but I had a very similar problem when I first started out with freshwater. It seems I was keeping my tank "too clean". I was vacuuming out the good bacteria and washing them off the filter. Therefore, there were not enough bacteria to keep the tank balanced. My tank kept going through cycle after cycle...

What helped me:

1. Biospira is a miracle worker...saved all of my fish!

2. Live plants (hardy ones like java fern, water sprite, even household ivy cuttings--just make sure there are no pesticides)

3. Less water changes. Water changes are important, but smaller water changes with minimal vacuuming of the gravel worked best for me.

4. Washing the filter media in the "old" water. When I do a water change, I rinse the filter media in the water I just took out of the tank. This way I don't kill the bacteria with chlorine.

5. Using a water conditioner that removes chlorine/chloramine and ammonia in newly added water.

Ever since I started doing these steps, my tanks have been healthy and happy...going on 4 years.

Hope you have as much fun in this hobby as I do! Take care!