When I was a young "eager to please" grower I always PH balanced my rockwool.. 24 hours @ 5.0 and I would SAY that is the correct method..

Years later.. still young.. still eager... I realize it just is not necesary to ph balance the cubes.. simply watering the cubes with 6.0 water as needed is all the young cuttings require..

ALSO.. I never water the CUBES directly (except for the first watering/soaking)... i always fill the tray with 1/8 - 1/2 inch of water and let the cubes absorb the water from the bottom..

of course... i get 100% rooted!!! LOL ..... of course