Thanks so much for your help!
I was leaning towards no grazers and lights on at night, now I feel more comfortable doing so.
By the way, you were spot on about the detritus build up on the little bit of live rock in the sump. We were keeping it in there until we got the refugium set up, and sure enough, when I took it out to place in the fuge, it was covered. Can't believe I overlooked that. I forgot to mention, our nitrates were at or around 0 (always below 5) until recently. I know it's not the change in salt that caused the spike, it just happened to coincide with it. That being said, the parameters have ALL been off since switching salts.
Hopefully I can catch my Sailfin Tang, that, extra water changes, a clean sump, a heavier (wetter) running skimmer, the extra filtration of the fluval and the refugium should help. *fingers crossed*
I'm debating on whether or not to keep the live rock in the fluval and just rinse it at water changes, or every other water change, partially because I don't know where else to put it.