I just wanted to thank everyone for the input and update the situation. I moved the fish into a more stable enviroment and the eyes and fins all look much better today. As for the tank, it was drained and the filters rinsed with tank water to remove any "sludge". The tank was filled back up and the pH not surprisingly tested at 7.6 (tap). Within 6 hours the pH had again dropped into the 5's. I finally went back to basics and realized the only thing "added" to this tank was a bag of acivated carbon. I removed the carbon and again drained and filled the tank. Been 24 hours and pH remains stable at 7.6. Never have I had carbon be an issue and this wasn't some generic stuff off some website. It was API which has long been a trusted brand. Of course I am not laying blame on carbon here, but all I know is once removed, the tank went back to normal.
Before the pro-carbon guys latch on....I know carbon doesn't effect kH, pH, or adversely effect water quality. If anything it adds to water quality. However, in this situation my problems began with the addition of carbon and ended once removed. I have never heard or experienced such a thing in 20 years of being a hobbyist and breeder, but this has been the solution. Tank levels are all back to normal.
Before the pro-carbon guys latch on....I know carbon doesn't effect kH, pH, or adversely effect water quality. If anything it adds to water quality. However, in this situation my problems began with the addition of carbon and ended once removed. I have never heard or experienced such a thing in 20 years of being a hobbyist and breeder, but this has been the solution. Tank levels are all back to normal.
