Ajay:
While the pH of fresh mixed kalk is around 12 and thus good to be very aware of, in your case a better way to approach this (than from pH management) would be from an alkalinity management perspective. pH is secondary (and linked) to alkalinity anyway. Also, as long as you have a relatively normal tank (skimmer, not too overstocked) and are dosing kalk through an ATO (which is the only way I'd recommend doing it) you're not going to foul up your pH.....misplaced worry as there should be very little kalk added in any given dose.
What you do not want to mess up is your calcium or alkalinity level. Do you know what your high and low levels (before and after water changes, usually) are for both parameters?
Unless you are seeing some calcium depletion (at first you will only see alkalinity depletion)
I would not recommend dosing kalk yet. I would suggest starting out with a two part system so you can add separate components - calcium or alkalinity by itself - as needed to keep things balanced.
This means you don't use any until you see a need for dosing
both calcium and alkalinity.
Once you have demand for adding both, you have a choice to make: kalk, two part, calcium reactor? Or some combination? Kalk tends to be the cheapest, but is inflexible and slightly dangerous to work with due to high pH. Two part is the most flexible, but can be very expensive if commercial solutions are relied upon. Two part DIY solutions exist. Calcium reactors are probably the cheapest solution, but are by far the most complex to maintain and the most expensive in up-front costs.
I suggest starting with two-part for it's flexibility. Cost should not be a factor for you at this point - dosing without error should be your only goal. After some time of dosing two-part, when the quantity (and related cost) of what you are dosing has increased and your skill at testing+dosing has increased, you can bring kalk into the picture. Since kalk adds both calcium and alkalinity, you will be able to lower your two-part dosing rate.
-Matt
P.S. If you have any doubts or hesitations about using kalk, listen to your gut and don't use it! Kalk is not a requirement at all and it does have some downsides that other dosing solutions lack.
P.P.S. If you haven't already, check out the sticky!