Prameter help please

[Saltfun2003]

Over that last 3 weeks my more sensitive sps have been slowly dieing. Polyps are still there but flesh is dieing off. After doing tests on tests ordered new test kits everything came out pretty much the same other then alk.
Current
ALK one test kit read 5.5 other one 6
calc 500
mag 1250
salinity 1.026
nitrite undetectable
nitrate undetectable
phosphate undetectable
Now alk is low i normaly keep it at 8.5-9 could this be causing the problem i am seeing? Mag is a little low usually its 1350. What is the best for keeping it up it usually keeps up with just water changes every 2 weeks.
I use a calc reactor for alk/calc would you recommend turning off the reactor till the calc comes down some and use bakeing soda slowly to get the alk back up?

 

[aurora]

Your calcium is very high relative to your alkalinity and you need to get the two in balance again. Your Mag is OK but can be higher like you said. I usually keep mine above 1400 just in case I get a bad batch of IO with lower than usual Mag. Definitely keep Mag on the high side if you are running a Kalk reactor. Make sure the outlet to your Kalk reactor drain into a very high flow area. You could be losing Bicarb from local precipitation and that would explain the imbalance. Make a short term adjustment in bicarb/alk using baking or washing soda. Turn off your Kalk reactor until you get your Ca and Alk back in balance. If you are using baking soda, the alk change will be noted the next day so do this gradually over a week or so.