What is wrong

[Parnold]

My lights are Hamilton, came with glass shield, dont know if it is UV shield.
I do run carbon.
Alkalinity is 100 mg/L tested with Hagen
I did start corals off low moved them higher after a week, I will try raising my lights to 12 inches off surface and cut back to a six hour time.
I thought the magnesium might have been low. Using aquacraft Meerzsalt and have since heard it is low in mag, have also noticed the coraline is not growing so much which I read is a sign.
Whatcaneyedo - it is me. The frags I got from you were not the only ones I lost. After seeing your coral I am pretty sure it has nothing to do with the specimens.
Will try retesting the ones of concern
What would be the best way to raise the Alk and Mag?

[BlueAbyss]

+1 on the nitrite, which is nearly as toxic as ammonia. GET RID OF THE NITRITE (and boost your dKh!) and your corals will likely stop dying.

To make it easy, I would use some commercial solutions to raise the Alk and Mag levels... they seem to be pretty straightforward with their instructions on the bottle, though I've only looked at very few kinds of dosing additives. Follow instructions and you should be fine.

Question, how old is your tank?

[whatcaneyedo]

I've used drug store epson salts in the past for boosting mag. For alkalinity I like baking soda. Heres a calculator that might help you:

http://reef.diesyst.com/chemcalc/chemcalc.html