I have a duncan that wont open after about 3 weeks. I have moved it several times and after reading up on it i placed it in the sand in a low flow area with low light which is what i read it should like. It opened the first 4 days i had it and now this. Next i have another which i was told was a favia from 1 person then another said its a war coral. It was growing and doing great until a few weekes ago when i had to scrub the hair algae off my rocks. Since it has started to bleach out and now is showing skeleton. I moved it a little lower cuz i thought the light maybe affecting it but it is just getting worse everyday. All my other corals are thriving. Palys get new heads every few days to a week, hammer is doing good etc. I have been doing 10% water changes a week and occasional 20% changes every few weeks to try to clear out the algae. There are 2 photos on the corals. Any help will be greatly appreciated!!