Hi, Dr. Holmes-Farley,
The HW Marine that I was referring to comes in at an average of 420 ca, 1240 mg, and about 9.6 DkH. No NO3, no PO4, and maybe a tiny spot (less than a thimbleful) of precipitate in every 40g batch I make. Mixes almost instantly and after dumping 18 cups of mix in the water while the Mag 9.5 is doing it's thing, water is absolutely clear after about 3 minutes. It really seems to be quite good. Pricy, but blew RSCP and Brightwell out of the water (no pun intended). I'm really fastidious about stability and this salt is really good. It mixes hotter than any batch of RSCP I could ever test out (RSCP parameters never have matched the hype in my personal experience) and no PO3 or NO4. RSCP is an algae grower in my experience. I must've used 20 buckets of RSCP before calling "knock it off".
Best,
Kevin