Will start with tank history. I started this tank august 1, 2017 and let the tank cycle for almost 2 full months and did a 30% water change. Then in October after testing and confirming the tank had cycled I added 2 cromis and waited for another small cycle. That happened and then every other week added more fish. Since the water 30% water Change I started the triton method and all water parameters have been dead on accept for 2 and they have not budged the entire time. They are Calcium which has been between 370 - 390 the entire time and the other is Magnesium which runs between 950 - 1000 and never budges from that area. My nitrates are not readable on the red sea test kits and phosphates are a constant 0.04-0.08 . My DKH is between 8.5 - 9.0. Salinity is always 1.025. No ammonia. Ph is constant at 8.0. Also the Light is a SBReeflight with par at water level 350 and 10 inches down 250 par. Also Flow in my IM40 is the return 500gph + a Icecap gyre 3k running 40%. For some reason which I think might be the mag and Ca levels I can not keep even the hardiest of SPS corals. Put a red monticap in the tank right in the 250 par area (tested with a seneye par meter) and in under a week it bleaches and dies. Then I tried another pricillapora cause I got it free for spending $ at a LFS and put it in the area that tested 300 par. I in about a week started to die so I removed it and took it to the LFS to try to bring back. Now my question Will the low Magnesium cause this coral die off? Or could it be the low Calcium that causes the die off. Or could it be a combination of both? Or is it something else? I am at a loss and want to figure it out and correct the problem before I get another coral. Any and all help is appreciated.