Peppermint shrimp eating mushroom coral???

[marknash]

hmm okay
well we have a 46g bow front tank, been running since july. we have a crappy toms aquarium skimmer/pump combo.. with an auto fill
( we think our lfs.. just sells us the stuff that benefits him at the time.. we had no idea the pump was not very good.. lesson learned)
we have koralia powerheads 1,2,3 (we were having cyano problems.. so we were told to add anohter powerhead and reduce our lighting time do you think this is too much flow for our tank?)
we keep our temp at 79-80, sg 1.025 ammonia 0, nitrite 0, nitrate less than 5
we have about 40lbs of live rock
2 clownfish, 2 bengai cardinals, peppermint shrimp, cleaner shrimp, fire shrimp various hermit crabs, 1 turbo snail, and 3 sand sifting snails
we just added a small green striped mushroom colony, and a small button polyp colony. we leave our lights on for 8 hours. we do weekly water changes of 10g ( is this too much?? ) we have a double t5 fixture anything else you need me to add?