clamp on light and cfl 6500k works wonders is on the higher side but mine is placed about 6 inches above the water and grows like crazy. Zoo med makes a lamp holder the double side tape to the back of the tank so it makes life very easy if you want to move the lamp up and down or just move the whole tank
I have a 5 gal. tank with a flat, thin lid, I think from Walmart. The led was not bright enough for me and I found some lights at the oznuim site, http://www.oznium.com. I got a strip of 6 lights and a controller. They are bright enough, and I think I could get by with a strip of 4 or 5 lights. I got the lights with 3 led's in a row. They are sticky on the back so I could put they up easily. I have had this up for a month and it is working fine, the plants like the light.