Tested a newly made batch of salt water. Salinity: 1.025, dKH : 13, pH : 7.8
That sounds just about right for Reef Crystals. Your calcium, on a fresh mix, is probably right around 490 so taking into consideration the accuracy of hobby grade test kits, your right about where you should be with that particular salt.
Is 520ppm calcium going to hurt anything?
No, it won't hurt anything, but there is also no advantage to a higher than normal calcium level.
I know lots of people comment their calcium is too high or their alk
is too high. There is a really simple solution. Change salt brands to 1 that has parameters closer to natural seawater or closer to what you want to run your system at. I use Red Sea salt which mixes to 400 calcium, 8 dKH alk
and 1300 mag. Those parameters are pretty much what I keep my system running at and they are about as close to natural seawater as you will get without messing with the mix.