From 9.5dkH went down to 7.3 dkH i think not to much.It went down to 7.3 dKH from 9.5 dKH and stayed there for about 2 weeks. In other tanks that might not have been an issue, but with my nutrient levels being quite high, I need to keep higher alk. Im usually ok if it stays in the 8.5-9.5 dKH range.
I've noticed high nutrients and low alk cause bleaching, tissue loss and tissue necrosis in my SPS. And low nutrients with high alk causes similar issues. That's why the zeo guys all run low low alk levels.
my tank dropped 3 dkH per days , Morning tes at 10 and evening went down 6.5 to 7 ...all my corals still happy until now