I have the same problem with IO. Even after 24 hours mixing with a powerhead, the last several uncovered, my pH is only at about 8. I have the same problem in the tank. (I use RO
from several different machines and the problem is always the same.) I was getting ready to blame the salt mix, but you've blown that, MarkW19! Thanks!
Anyway, no advice but I will tag along to see what others suggest.
tank with 29-gallon sump
2x Maxijet powerheads
Mag drive 9 return
Coralife 4x65 Lunar Aqualight
120 lbs rock from liverocks.com
1 peppermint shrimp and 1 fire shrimp (very shy)
2 black Ocellaris, Squish and Smudge
3 chromis, too identical to name as yet, in QT
29-gallon with two goldies, Carrot and Orangehead