You got everything right. The one thing I didn't mention was that when I make new water I let it sit over night with a pum and a heater. I had checked to make sure the tank and the new water matched the night I made it but didn't check the next day when I did the water change like I usually do. I just remembered that after reading your comment, cause you're right, something has to be going on. I think its possible that more salt dissolved overnight which raised the salinity in the new water, which is why I usually check right before putting the new water in the tank.Agree with everyone else, most likely this is not urgent and you can lower your salinity over time. But I am still not sure about what is going on.
Feel free to just stop me if I am just too lost, but if I understand you correctly, this is what happened:
1. tank at 1.025 yesterday, before water change, measured by refract #1
2. water change done yesterday, makeup water matched to 1.025 with refract #1
3. Found refract #2 today, calibrated it, and discovered tank at 1.027
4. Checked tank with refract #1 (did not recalibrate this refract between today and yesterday), 1.027.
Refract #1 and #2 are in agreement today, and since #2 was calibrated today, we are assuming that #1 is reading correctly today as well as yesterday.
So that means that after your water change yesterday, your tank was at 1.025, and something raised the salinity to 1.027 overnight. Evap loss and/or temp swings will affect salinity, but on 150 gals, wouldn't that need to be a pretty significant change in a short period of time?