I am not the least bit surprised that is your phos level. You have some nice big fish that need to eat more frequently and larger volumns. While that level may contribute to issues with some sps ( such as coloration and PE ) it should have no effect on the fish. If it continues to increase, I would suggest some phosban, GFO, purgien....eqiv. Possibly some mangroves if possible. And I agree the phosphate level may actually be higher as some of the phosphates are now bound up in the algae.