I used
Coralife - Ca, Mg, alk were high but something wasn't quite right and I never got the colors in SPS
Seachem - Ca, alk high but Mg deficient Better colors but bulk magnesium is probably needed. I needed 2 kg of Seachem mag to boost one bucket's worth or salt.
I agree with cbusreefer about throwing your parameters of in a water change. If you are going to the trouble of maintaining Ca and alk with daily doing to minimize the swing of ions in your tank, then why would you want to deal with a spike from a necessary water change.
It might be possible though, to use the water change to have the same Ca, and alk boost to your system as one day's worth of dosing (two-part), and then skip the dosing that day.