i agree... running a fan on the plants, medium speed(reccomended), as well as foliar feeding them will strengthen the stem so the plant stands up on its own. when the plant toppled over.. if the stem snapped, then the capalaries inside the stem have broke and will not be able to carry water and nutrients to the middle and tops of the plant. if it just flopped over and didnt break then your good... brace the plant, foliar feed to add weight to the leaves and then run your fan non-stop. if you have more space in the pots you planted in you could also add soil to it to brace the stem further.. hope that helps, good luck
also if your water is pH'ed at 5.5 that is way to acidic! MJ likes water that is slighty acidic, ideal pH is between 6.3 - 6.8, instead of buying expensive chemicals for pH Up and pH Down, you can use Distilled White Vinegar for pH Down and you can use Arm & Hammer Baking Soda for pH Up. cost you around $4 for both at your local grocery store! also, if you're using tap water for your plants, make sure you let the water sit out, opened for at least 24 hours so unwanted chemicals such as chlorine can disipate. another option is place open, empty jugs outside when it rains and collect the rain water. its all natural and perfectly pH'ed by nature for your girls!
nah they dont have to be at 5.5, the plant is going to absorb the water from the rockwool. its what the plant requires as far as pH goes, not the rockwool. if it snapped it might b gone... but keep it braced, feed the plant by spraying water on the leaves(foliar feeding), maybe it'll turn itself around! who knows stranger things have happened!