I haven't used rockwool myself but I've HEARD of it's ph issues. Next time I'd probably soak the rockwool (and keep checking the ph) until it stabilizes at the ph I want. May take longer than 24 hours.......I know it does when prepping hydroton.

At this point, just keep checking and changing it back which you may have to do several times a day for now. The issue will improve when you get some nutes in there with their ph buffers.....and the problem WILL go away eventually as the medium stabilizes.
Weedhound Reviewed by Weedhound on . Too soon for nutrient deficiencies? Drip T5 Distilled water @ 5.8 69-72 F 40-42 RH 18/6 cycle Watered 3x daily @ 10 min. increments. These 2 are in the 9th day of light. T5 sits 3-5 inches from top of plants. I've noticed they have slowed in growth and developed leaf discoloration. From what I've researched it looks like a P deficiency. Is it too soon to have nutrient deficiencies...? Rating: 5