Don't feel bad, we've all been there. Your sps are def not liking the high nitrate. Even 14 is too high for sps.
You need to figure out the source. Has your skimmer been working properly and pulling lots of gunk out regularly? Have you been doing regular WC?
If those are both yes, does your sump need cleaning? Check the rear power head chamber. I'm guessing a build up of detritus and possibly over feeding if the first 2 are being done.
Thanks for the encouragement. I increase the water change to twice a week at 15%. I think the feeding is on par, because all the fishes attack during feeding as if they don't have enough. I do use a micro filter sock for the downflow/overflow to the sump, I wonder if that traps stuff that needs to be dumped. I change the sock once every week or two.
The skimmer has been acting strangely. A couple of times in the last three months. It started to over skim and flooded the floor. I had to lower the setting and not have readjusted after the last incident. It was filling about 1.25 gal in a week, it slowed for some reason and then it over skimmed when I was trying to adjust. I hope it is more steady now. I am usually away for work Mon to Thur. so I only have the weekends to take care of it. My daughter has been doing a great job keeping watch.
I use the stock skimmer by red sea that came with the tank, and had no previous problems with it. I clean the gunk via the "force cycle" of the chamber once a week. The top I don't normally clean until I see "gunk" beginning to fill the reservoir area (which I have a hose redirecting the output to a 2.5 gal slim water jug.
By way down in Nitrate, I am still using the 15 par RO and 1 part tank water and it is very light pink. Will try the full 16 part tank water this week.
Tom