That is play sand that I have in the tank, not tiny gravel.
The light fixture only cost me 14 dollars. Just go to walmart and go to the lighting section, and in the flourescent strip light area, there are 24 inch light with 17 watts of output for 7 dollars each. I bought 2 of them and attached them together with silicone and tape. I also made a reflector out of aaluminum foil.
I eventually upgraded to 20 watt lights for an extra 10 dollars. I get 2 WPG with that. It look a lot better now after the Ludwigia grew in, except that the Anacharis melted and now I have to buy some more.