I haven't had that issue yet. Who knows if it'll crop up at some point. The worst thing I have is the discoloration from the nutrients. My rez stays a consistent 70-72, but I'm working on a chiller to get those down closer to 63. I don't use any medium, though, so I don't know if that might be something. I just have them hanging in the neoprene collars in the net cups. I use 2" cups. Do you use all

nutrients? I've never used those, nor really seen or felt them. I don't know if they're anything like Floranova (real thick) but the Botanicare stuff is real watery. The thickest thing I use is Liquid Karma, and that's still nothing compared to Floranova.