If the rock is in the dark nothing except bacteria should be growing. No change necessary.
ARe you going to keep fish only, or coral? Sometimes new rock absorbs a lot of alkalinity from the water. Test and see what you get. If the rock is absorbing alkalinity you could start dosing if this is going into a reef.
Also, some new rock will leach phosphate, so test that also and treat it now if you are getting any.
GL