How deep is your tank? I believe PC's are really only effective to about 14-16", also how old are the lights? from what I have heard PC Bulbs last about a year at most. I am not bashing PC, I am currently running PC on my tank as well, just making some guesses.
I also noticed you did not post any information as to the frequency and size of Water Changes you are performing.
I really do believe that water changes are the most important part of your maintenance. Not only do the corals look better when I keep up with them, but the water does stay much more pristine.
Another thing to consider is Carbon. I did notice a big difference when I started running carbon in my all softy set up. I thought my water looked good before using carbon, but there is a really noticeable difference even after just a day or two.