Monti question

Hello, I am new to Reef keeping a 3reef so I hope someone can help. I have a 75 gallon tank w/2 175MH (10K each), a G1 protein skimmer. I leave the lights on for about 9.5 hours a day. A few weeks ago I bought a "Montipora Cap" (what the person I bought it from said) which was tannish/brown. The peice broke in half on the way home but I put both peices in my tank, midway up and with moderate water flow-both at least 4 inches from any other coral. Within two weeks the two peices were completely white. This occured slowly over the two weeks. There were never spots or anything else on it and everything else in tank (mostly softies) were doing fine. At the time I put the montis in my tank the parameters were
Ammonia-.25 (a few crabs had dies and I was still working on getting the ammonia down, only lasted about one week being at the not 0 level)
Nitrate-20ppm, Nitrite 0, PH-stays consistently 7.8, alkalinity-170, Calcium-520 (is now down to 500). Salinity consistently 1.025.
Please tell me what would have caused the Monti to go white so I don't kill another one eventualy!!
Any other feedback appreciated cause I'm new and still learning.
coraladdict

 

I'm certainly no expert....but any amount of ammonia is definitely not good, and your pH is too low. I can't say about your alkalinity as I only know dkH ranges?

 

That ammonia is not good for corals or fish, it burns them. IMO, that is probably what did them in. They could have also bleached or have monti eating nudibranches on them or in your tank, or the soft corals could have released chemicals which killed them.

 

GuitarMan89-
Uhh, should know this but what causes the bleaching? I have read too much or too little light?
coraladdict

 

Usually too much light, or not properly acclimating the coral to the new light.