I'm sorry to hear about your tank.
You mentioned not having enough water on hand, and using tap water in a pinch. Steve Weast did the same thing and almost killed his entire reef. Unsure that it was the tap water or the de-chlorinator, but one or both killed the majority of his livestock.
I would immediately get some Polyfilter (the actual real product, not some likeness thereof), and run it in your baffles. It will change color based on what it is pulling out of the water.
When you lack water, the best thing you can do is run to the grocery store or Walmart and buy as much distilled water as you can get your hands on. It will cost you about .59 per gallon, but it is completely safe and works when you are otherwise stuck.
Another thing to do when you lack water is to focus on the display only, and take the sump out of the equation.
You'll want to dose the tank with Seachem's Prime (reef safe), which will lock up ammonia and nitrate, and is a de-clorinator too.
Test for ammonia immediately though. Your tank will definitely cycle.
If a coral is definitely sloughing off tissue (turkey baster will make this obvious), pull it out so it doesn't add to the decay factor in your reef. Any live tissue is a good sign, and hope that it will recover in time.
You did a great job bring salinity and temperature up in the past 6 hours.
SpaFlex can indeed be glued, but it also must be supported if it is a lengthy section. It is important to use the right glue, and that the fittings are the correct kind. Many people try to use waste line fittings that have a 1/2" deep socket, but should have used the normal fittings that a 1" deep socket to glue into. The deeper socket is designed to handle pressure, while the shallower socket is for drain water that usually doesn't have much pressure behind it.
