I've come to the conclusion that my nitrates are WAY to low - <.01ppm. My P04 is around .03-.06 consistently, but I think that the tissue recession and lack of PE that I am seeing is a result of my Nitrates bottoming out. I feed a lot of brine shimp, PE mysis flake, veggie pellets, and seaweed, but there is a lack of coral food. It could also explain the issues I am having with my maxima clam - it is not really extending it's mantel despite my attempts to relocate to correct for lighting and/or flow issues. The derasa, however, is growing like a champ and is on it's way to doubling in size within three months (it was only about 1.25'' when i got it, but still!) STN from the base of the purple bonsai continues with some burnt tips, montipora setosa is losing color and possibly tissue (hard to tell).
I have bottles of NeoNitro and NeoPhos being delivered today, so hopefully I can right this ship. I had problems in this area with my last tank.