I would let a good salt do the work until you see that you need to dose something. It's real easy to use.
Start out slow and follow the directions on the label. After you mix w/RO you have to let it settle for a couple hours. You can skim off the top (solids) and place the drip tube about an inch off the bottom of your container. You don't want the stuff on the bottom (again solids). Drip in the sump very SLOWLY!
I have a link somewhere about mixing the klak w/vinegar this is what I do, you don't have to wait before you start dripping. I think I may have some other stuff on here to. I'll see if I can dig it up.
Do a search on kalk, plenty of stuff out there. My tank loves it! I've got several SPS that are loving life!
HTH
Tim