Need help. Tank is going south

I have a 125g saltwater tank. It has been set up for a little over a year with very little issues. I only have 2 damsels in there and a couple snails. Being very coutious this time around. Over the last month the sand and rocks started turning brown, almost like dirt or dust. 2 days ago the tank started getting very cloudy. Any ideas what is going on? The only thing change was I switched to led light from 2 t5 bulbs about 2 months ago. Any help would be great. I will try to post some pictures.

http://ift.tt/1RSoOpt