Questions - Need some input

Hello all! For lack of better terms I would consider myself a "water nazi". I sample my water at least three times a week to verify everything is at its proper levels. After I test my water, I usually make a trip to my local LFS to make sure my tests are accurate. The last test I conducted yielded these results:

PH - 8.2
Salinity 1.025
Phosphates 0.0
Nitrates 0.0
Calcium 500
Magnesium 1350
Alkalinity 8.9

About my tank: 75 gallon ...