The bamboo is looking great! Nice setup hydro.
Yeah that bamboo is a neat little plant, but it sure is slow. I have a couple of collector bamboos as potted houseplants and one would think that they would be easy to grow and real fast like any other grass, but they are more complicated than that. Bamboos seem to have to build up a lot of energy in their root systems before they can spread and grow very much.
Here's the foliage of that nice full potted plant that I bought.