Alright look its already been established that your plants are stretching, a good for sure way to stop the stretching, is by taking your thumb and forefinger and pinching the stem to break the surface. Now just like a muscle when you tear it, it heals back stronger. This is also a way of...
You deffinately over watered them and your ph level in the water isnt high its average but if the plants are still in rockwool place them in soil if you think the roots are strong enough at this point and then after a few days try adding some fertilizer then your plants should be healthy but...