Hello all,
MV is right about soaking the rockwool before using it. That is really necessary before using them for your plants. Also consider wearing a respirator when working with rockwool because all those "fiberglass" particles can be nasty. Those particles are also know to kick up and can stick to your buds. Pruning off the lower parts of your plants can create a buffer zone to help that issue.

If you are looking for cheap ph up and ph down, try baking soda (up)and lemon juice (down).