I still have one left..how large the leaves can get? do you think the light that i have right now is enough?( just 2 x 15 watts tubes) the same light that came with the tank when i bought it.I think that it will grow pretty well in there.
This could be a good plant for that setup of yours shrimpo. DO you still have any of those planters left? I have often seen Diffenbachia like this one and similar among the houseplants in grocery stores or at Home Depot or wherever. They are common houseplants.
The emersed plants are doing fine so far exept the foreground plants due to duckweed plant start to cover the surface.(and possibly not enough light for them to start with)Are your other plants growing in that light? I understand that Diffenbachia only need moderate light, so if your other stuff is growing then it will probably be sufficient. However, 30 watts is pretty dim, and I imagine that the fixture probably has T12s. Is that right?
You might try looking around for one of these where you see houseplants for sale.