Definitely not the salt.
All my levels started off low (and stayed low obviously) because I started out with Instant Ocean salt.. and didn't dose anything for the first 2 months the tank was up.
I did one 10g WC with the IO then when I switched to ESV salt I did a 20g WC.
Today....
-Changed out carbon
-Did 10g WC (w/ ESV salt), brought salinity up to 1.026 (was at 1.023 previously)
And thats about it.. besides debating the entire day on what to do.
As Batt600 said... I have what I'm now FINALLY understanding is TOO MANY LEDs lighting my tank.
When I first set up the LEDs (before I even had the tank in my possession :lol

I had 18 Cree XR-E White & 18 XR-E Royal Blue with 70 degree optics, and 3 non-dimmable (constant current) drivers.
Naturally I wanted independent control of the White and Blue... but with 3 drivers that wasn't going to happen.
So I ended up creating
2 Drivers - Controlling mixture of white and blue
1 Driver - Controlling on Blue...
I wanted a bit more blue when the daylights were on... after seeing Jarrett and Dr. Harry's tanks with their 20,000K Radium MH bulbs... I was really set on the bluer look..
And for some reason I thought there wasn't going to be enough light...and it was going to be the same price to either add 12 more LEDs and a non-dimmable driver OR replace 3 existing drivers with Dimmable ones (which I probably should have done).
And I obviously (stupidly - not knowing better) opted for MORE light... I figured getting everything bigger better and brighter was the way to go... well that is obviously kicking my buttocks pretty hard right now.
The color of the tank with daylights on is really awesome... but its just way too PAR or light intensity for the corals to handle... some are actually absolutely fine... but some aren't opening. What I find weird.. is that it took 2 months of being blasted with this light for it finally to show some signs... that it was indeed too much light.
I think that even if I bring the fixture up its going to be too much light...
So starting today I'm just running 2 drivers (the 2 that control both blue and white)... only thing that sucks is it ends up being 18 White and 6 Blue.... so the tank looks pretty yellow... and the spacing of the LEDs creates an ugly light pattern because the blue LEDs are far off to the right and left... basically leaving a beam of yellow light in the middle.
Soo... overall I think my whole problem is 2 separate problems that combined together...
#1 - Lights WAAAAY too strong.
#2 - Cal, Alk & Mag too low (reasoning for why SPS is not happy any more in addition to surplus of light).
Unfortunately financially right now I won't be able to do anything about getting dimmable drivers..
So I guess I'm stuck with using 24 LEDs for now... with a tank that is an ugly color...
I don't think egg crate will really do anything.... it barley diffuses anything...