Buff it up buff it up. Kh quite low wor.
Hey, one question, if you are ordering a new tank, why cycle and stock this one?? More headache to shift later isn't it??
And you are right, he test kits are quite basic. They are essential to do diagnostic and tuning of CR or dosage volume... however the 2 "non-vibrating" probes are good to have (IMHO)
ORP, never measure.. Fishes are doing fine. Not sure of ORP affects corals though.
Whereas ph will be somewhat stable if kh is constant.
Then again, I only have a very short 1 yr experience with SPS, I could be wrong.
Btw, since you are tracking po4 closely now, would you be curious to know if water change can export po4 and no3 faster than GFO?