Sorry to hear that Bwinder.
My hammer seems to be doing pretty well. Here are my specs and maybe I can help with ideas for yours. I will admit my parameters fluctuate, but, I wouldn't say by much. I ATO to keep my salinity consistent. I also do a 20~30% WC every other week.
Alk 8.0
Mg 1350
Cal 440
Nitrate, Nitrite, Ammonia, Phos all undetectable
SG 1.025
Temp 79F
I have it positioned about 16" under a 6 bulb t5 and off to the side of a mp40. It gets current but I would say it is gentle.
My Magnesium was also low (before I corrected it) but that never seemed to effect any of my LPS. The only thing I can visibly notice when my magnesium is low is that I get more nuisance algae growth and slower SPS growth.
Finally, my frogspawn, hammer, and trumpet coral LPS seem to be the happiest with 2 or 3 mysis feedings a week. Sometime I will feed mysis or rod's once or twice and feed coral food once a week. I try to vary the diet as much as possible.
If you need some pics to help describe location and or environment let me know. Good luck.