what alkalinity you guys get ?
And that's part of the reason I choose IO over RC. The alk is a bit high, plus there are more trace elements in IO than RC.This bag of RC mixed at 11 alk, off the chart on the mag, and about 460 cal. Not sure what the others will be but I'm sure they will be different.
RC for me. I've never really bothered to test the parameters though. I try to keep my Alkalinity around 9, my Calcium between 420-450 & the Magnesium between 1280-1320. Unless the parameters of this make up water are way off base a 10% water change isn't really going to sway anything one way or the other.