I just made some clones and they rooted in 14 days. I did not have to re-soak to rock wool once! I PH some tap water to 5.5 then soak the rock wool in that for 24 hours, then I insert cuttings with some clone stuff i got.

My clones sit in in a humidity dome with 23 watt florescent above the dome. I wish I could keep them warmer but oh well. I open the dome once a day to refresh the air normally i never have to add more water to the rock wool until there are roots. Probably because its cool here, not cold but like 70.