when I mix ocean pure pro in a new batch at 1.025 salinity, I get 420ppm calcium, 7dkh ALK, 1550 mag. Sometimes I get around 6 dkh/380 calcium, so I just add a little two part using a calculator before-hand.
I test all my change water before adding it to the tank. I also make sure the water is aerated/heated for a day before I add the salt, then aerate/heat it for another day. I think quickly heating the water while dissolving the salt lowers it's levels, or adding it to freshly made RO/DI water is detrimental because of the high CO2 content causing an out of whack pH. Plus it doesn't hurt to do it the slow way
