Maybe 2 or 2 1/2 months. The last time I attemped this, the Cory cats kept uprooting it and pissing me off so it never really took off. Just floated in pieces everywhere. I have some Marsilea quadrifolia in the back (right side).
I started with small pieces and inserted them into the substrate all over the front. It really likes the ADA Amazonia and once it got rooted, just shot up! My camera really doesn't do it justice, but here is another shot of the front. The first pic is from the right side shot.