FWIW, I've gone thru two 200 gallon buckets of the stuff with no remarkable change noted in the condition of my animals (various LPS & SPS & a few fish) one way or the other.
I am a bit anal about testing anything that goes into the tank, so I can say the following with as much confidence as
Salifert test kits can give;
RO/DI water mixed to 35 ppt (1.026 Sp.G.) @ 78 degrees F
420 < Ca++ < 450 (ppm)
7.9 < pH < 8.1 (after 12 hrs of mixing)
7.8 < dKH < 8.3
1300 < Mg++ < 1350 (ppm)
So far, these values have been quite consistent.
- Bert