mr_X
Aquarium Advice Addict
Cool. Now test every day for about a week. This way you'll know exactly how much you are using in a weeks time.
LOL...you need to know how much your system currently uses per day. If not, your alk may go down then up when you dose, then down again ....corals will not tolerate this. Trust me....you don't have to do it every day forever, but until you can get a pattern established.
Coralline isn't going to change things that much. A large stony coral load may, but then this is what you need to be aware of. It's called "reef keeping".
When are you going to add? Once a week? This is not going to work. Your alk will fluctuate and this is what you are trying to avoid.
Mag won't need to be added that much. I'd rather see you do alk and calcium at different times of the day.