I have a D & D Nano-Cube 12g and I have heard good reports swapping out the sponges in chamber 1 for live rock rubble and ditching the active carbon and bio balls and creating refugium in chamber 2 and let cheato grow, but this requires require a light source for chamber 2.
My question is: Do you know of any light products which would meet my requirements?
I've been told it is better having the light source from the back after removing the vynil covering from chamber 2 rather than above as this spreads the light better.
Live rock and live rock rubble is always a good idea in any tank and I would have thought that you would still get enough light as standard for copepods etc to grow in the back without modifications if you simply want live food.
Algae of course would be a different matter and perhaps a short fluorescent tube of about 6w could be fastened on the outside however mods of this sort are at your own risk and I do not have any other suggestions for you I am afraid.