I recently had a salinity increase. I top off the tank with some Rodi water . No ammonia. N02 no3 is 5pm. Phosphate are at 0 calcium 420 . Alk is 8.5 mag Is at 1400 . I think it was the salinity swing.
I recall that you’re new to reefing. How old is your tank? SPS is usually recommended for older tanks and experienced reefers. Not saying you can’t do it. But SPS need spot on conditions to thrive. Stability of your tank is probably one of the most important parts. Then lighting and flow.