110G Start Up

[CountryBoy72]

I now have 100lbs of macro rock, 44lbs of LR, 105lbs of dry sand in my tank. I have an flow accelerator on my return out flow, a 1400 gph powerhead. I also have my protein skimmer running too.

My parameters yesterday were
Temp- 79.9
PH 7.5
Ammonia .6
Salinity 1.024(little bit below)

Tested my salinity today an it jumped up too 1.030 I removed some of the water an replaced it with RO water. What would cause it to jump up like that ? An how long does it take for the salinity to drop once I put the RO water in ?