from everything I've read, it's best to disassemble it and plant the plantlets into the substrate. i'm in the same boat except mine's on rock. I put planted the rock under my flourite substrate with just the tops of the HC sticking out. It's been less than a week and I've already noticed some new runners, so I'm hoping that this will work, but I'm skeptical whether or not it'll actually take. I'm hoping at best that it will and at worst that it'll spread into the substrate while what's left on the rock will probably die off. Good luck to both of us!