Interesting experience. Isn't natural sea water in the 7-7.5 dkh range?Possibly your referring to the quick raise in DKH levels but if not…
That’s odd I run 12 DKH solid. I don’t look for 8.5 or 9 DKH.
I use Red Sea coral sea salt which is primed at 12 DKH.
I have 80% maricultured (wild coral) in my tank. Everything lives, puffy, swinging and growing.