Don't chase pH, it's a losing battle. Keep ca, alk and Mg in line and pH will follow. Kalk in your ATO is the easiest to keep alk in line, 2 part if your tank uses more alk than kalk can provide.
I'm on kalk. I agree, the only number you should really be concerned with is alk. If that is in check you're likely in check with everything else as long as your nutrient levels (nitrate and phosphate) are in check. Ph is not a variable you should be concerned with.
Also, I have a decent amount of sps, and I thing it will be quite some time before I need to switch it up so something besides kalk.
Don't chase pH, it's a losing battle. Keep ca, alk and Mg in line and pH will follow. Kalk in your ATO is the easiest to keep alk in line, 2 part if your tank uses more alk than kalk can provide.