lighting is 2 250 watt 20k reflux se with to 54ho atinic+ halides are on for 8 hours a day and t5s for 10 hours. yes i do run carbon 4 cups in to bags run in a fluval fx5 canister along with gfo. i change 2 cups of carbon biweekly and the only thing in the canister is carbon and gfo and this is cleaned out every other week when i do a 20 gallon waterchange. bulbs are at max 6 months old so i doubt that is the problem. i have been growing a blue maxima on the sandbed for over a year so i know that my lighting is sufficient. no aefw or red bugs i have checked countless times and can never find anything. the only thing i have ever seen was a hairy leg crab brownish body and black claws. this has been in my yellow acro colony before but i have never seen it eat my acro. i saw on a thread last night about how hairy crabs are bad and may be eating or stressing out my acro. this could explain the problems with the yellow colony that i am having and as soon as i see this crab again i will get it out of the tank. but i have a brown with blue tip stag and this has completely browned out after holding its color for months now this is suffering from a severe case of rtn more than half of this small colony has been affected and i have never seen anything bother this coral. (i watch my tank alot at night with red led flashlight) so i know that this is not a pest on this one.) so the only thing i can think of is the alk. as far as the softies go i have pulsing xenia, kena tree, a yellow lether toadstool, and waving hand xenia(the non pulsing kind), orange ricordia mushrooms, blue/purple mushrooms and green bulseye mushrooms. other corals are dragon eye zoos, orange zoos, eagle eye zoos, frog spawn, candy cane coral, green open brain coral, a medium colony of suncoral, orange montie cap, green montie cap, purple montie cap, a blue base purple polyped encrusting montie, and orange montie digita, and large colony of button polyps. none of these other corals are affected and all the softies grow like wildfire. the lps and monties dont grow real fast but all have great color. like i said it is only sps that are affected. i think i have answered all questions but if there are any more please ask because i am really wanting to move my tank to an sps, monti, clam, and maybe some really cool zoos but not if i cant figure out what is going on. i really dont want to buy great looking sps just for them to brown out in my tank.