rock wool prep question.

I know you soak rock wool in PH adjusted water prior to use. Can I soak and dry a bunch for future use? I want to soak, dry, and then zip lock bag store some 3 inch blocks. Will the PH stay down or go back up when they dry?
I figure as I am soaking some, I may as well soak them all.

No. Presoak them before you need to use them.