roots have grown down the pvc

[pvc]

hey ron,400 hps again, things are much better now with venting,18 hours on time, they are doing much better. I have come across another problem, i told you before i was using rockwool, the thing is the roots have grown down into the pvc, not the problem, the problem is that they are clogging the hole, and a couple aren't getting water up in the rockwool, they still get water on the bottom roots, so they are still alive, but not doing as well as others, I don't think i can do much now, but prepare for future plants. ever hear of this? thanks