Hey Richard,
I was a little disappointed with my new bucket of Seachem Reef salt. Besides leaving a lot of residue behind, here were my readings.
First, it took 27 cups to make 45 gallons of mix @ 77.4 degrees to make SG @ 1.026 and Salinty of 35 using a calibrated refractometer: Usually, with other salts, it about 24 cups.
KH was 8
Ph 8.3
CA 400
Mg 1125
Not great, but not bad either, as this stuff was $35 a bucket at Aquatic Central. It doesn't buffer real well even after a 10% W/C. So I do what these companies like, add their chemicals. I'm almost ready to buy a sack of baked baking soda to help out with my KH and my 2 part doser once I get it set up; and some other chemicals to maintain CA and MG levels too.
If you find any salt you're very please with feel free to add it to this thread. I'll check back from time to time.
Thanks for bringing this topic up. H)
Best,
R.K.