If you add it all at once, you should add it at night so your PH will not go to high. If you drip it, you can do that throughout the day.
If your calcium requirements are low, then only use a little kalk per gallon. Right now, I have high calcium requirements and I am just starting to drip kalk, I am starting with 1 teaspoon per gallon. If I need more, then I will adjust later. If you have little requirements, then try starting with one half teaspoon per gallon.
You will not hafta add strontium, and your magnesium level depends on which salt brand you use. A lot of people, myself included, have had to add mag when using Instant Ocean, but after switching to Oceanic, we no longer had to add it.
Do you have hard corals or a lot of coralline that you think are depleting you calcium level?? Because if not then your calcium is most likely being replenished via water changes.