Kalk and Alk?

[kaserpick]

Hey guys, I have a 30g modified breeder tank. There are about 30 corals consisting of mainly SPS and zoanthids. I have around 15 SPS (mainly frags), 2 Clams (Crocea and Maxima both around 4-5"), and 1 Plate coral; the rest are zoas.

Have a few questions:
1. Will Kalkwasser affect Alkalinity (raise or lower)?
2. Will Kalkwasser maintain Mg as well as Ca?
3. I'm adding around 1tsp Ca and 1/3 tsp Mg everyday with no ill effects (both are powder by Tropic Marin). Do I still keep adding as much while using Kalkwasser?
4. If I use Kalkwasser, then is using it in top-off at the minimum dosage everyday too much?

I do weekly 7 gallon water changes; my Alk is 9.6-10.0 dKH, and my Calc is 390-400ppm (fluctuation depends on how long in the week it is for both) and Mg is around 1150 now (I'm slowly raising it until I am in the upper 1200's). I use Salifert test kits for all three.