My 2 cents, salinity just a tad bit low and your Ca just a tad bit high. All others parameters look good.
The key to keeping SPS is stability. I know you had a temperature fluctuation I believe in the last couple of weeks. If you remove all fluctuations of parameters and keep it as stable as you can, the SPS will respond. They won't respond right away either... it could be going good for weeks and nothing. But over the long haul, the fruits of your labors will pay off.
To me, the other key is knowing your PO4 level accurately. Less than 5ppm is just the start with PO4. If you can get it down below 0.1 ppm, you're doing pretty good already. The trick is to know it more accurately (I recommend a Hanna meter) and to maintain it at that low level without a lot of fluctuations is the key. No polyp extension is usually not ideal. It's alive, but that's it. When it's happy is when you start seeing all the polyp extension, at least that's what I have observed.