Alk 7 - 14 dKH (best health occurs at ~7-12)

Ca  350 - 600 ppm (best health at ~400-500)

Mg  1050 - 1800 ppm (best health at ~1200-1400)

It should also be noted that Alk and Ca are quite forgiving, or in other words, coral can often live pretty well anywhere within the ranges shown above and usually take a fairly long time to be affected by out of range levels. In a sense, that's why we test Alk and Ca, because unlike Ammonia, Nitrate and Nitrite, we cannot see clear, immediate evidence in the coral when Alk, Ca and Mg levels have gone out of range. 

You didn't say what lead up to this concern about testing and dosing. That history may be important to consider. Did an animal die? Was the coral looking bad? Did you read or hear that certain numbers were imperative?

One other point: Chasing numbers can sometimes result in catastrophe. I've seen it more times than I can count. In these cases, the natural chemical equilibrium of the water was messed with until chemistry was out of whack and animals started to die. Sometimes letting the tank reach its own equilibrium is healthy. 

It's always helpful to fully discuss the situation with knowledgeable reef keepers that can lead and guide you to safely reach a reasonable goal. It may seem strange, but that's what we are here for. The purpose of this club's founding was to help each other have a better reef aquarium.

Aloha,

I test Alk about every 2 weeks or so, Ca less often and Mg maybe 2-3 months apart. I test PO4 only every once in a while but NEVER test pH nor N compounds(NO4, NO2, NO3). if you would like to know why I can get away with so little testing, I'd be happy to explain.