I am unable to get a coral to stay alive in my tank. 26 gal with 25 lbs live rock,50 lbs live sand, 70 watt MH, sump, asm skimmer. Cycling started may 10th. June 24 put in a hammer coral which never did a thing. It had 3 good stalks and after 2 died quickly (2 days) I got it out of there. A true perc and scooter blenny put in the same day are doing awesome. On July 1 put in a small Galaxy Coral which looks to dying off now. It has never come out of the skeleton since I got it home. Yesterday the LFS gave me a small Xenia which looked good for a couple of hours in my tank but now looks awful. What could be going on? PH is 8.3, calc is 400ish, alkalinity is 14, temp is between 78 and 80. Ammonia, nitrite and nitrate is 0.