I agree, in my high growth tank it grows at least an inch per day, that's planted. I don't find that it propagates very fast though, at least compared to its growth rate. Since it only seems to branch at specific points you're kinda limited in where you can propagate from. Even then, I still figure I could probably come close to doubling my stock each week. It won't be in that tank much longer though, I'm moving the last of it out into a slower growth tank, little wonder.