Tootie,
Fluctuating ph might also be a stressor and causing part of the problem. If your ph is fluctuating, you will have to "age" your water before adding it to your tank when you do water changes. The day before or even longer, pour some tap water with dechlor into a bucket or barrell with a heater set to the temperature of your tank. I would also put a large airstone or powerhead in the bucket or barrell to circulate the water well helping it to gas out. This will help your tank ph stay consistent, and you won't be having to add ph up or down to try and keep it stable.
