I've been using Seachem Reef since May of '08. Before that was TMPR, than Oceanic, than IO before that.
I used to test, test, test, test, test, test.............................Now I test every other month or so................
My PH, Calcium, Mag, Alk never waver (I also add 2 part on a cheap aqua-medic pump 4x daily).
Every time I did a water change prior, I had to add this and that, due to the fact that the water change depleted everything!
Only thing to remember is subtract about 2 from your dkh because of the high level of Borate Alk (corals need carbonate alk)! That keeps everything soluble & ph straight!