Mine took only a few months to give my tank a makeover! I wish I had known it needed to be pruned before it spread this much. Now I'm going to have to "harvest" it in stages so all the slime doesn't **** off everything else in the tank. I have a pair of really sharp scissors just for aquarium use. I'll cut them as close to the rock as possible, and place them in a breeder net with the rock for them to attach to. I plan on zapping most of the stumps left behind with kalk paste to keep it from growing back. Then I will keep the rest of it under control with regular pruning. HTH