Hey I decided to give this moonlight thing a try so headed down to radio shack to see what they had. They carry 5mm blue led's that peak at 430nm and have a output of 300mcd at 5v. All moonlights I have seen have been 470nm but figured I would give these a try for $1.99 each. I wired 4 led's together and took a cheap dollar store flashlight reflector and used epoxy to make my 4 led bundle stick in the reflector and then hung it on one side of the tank to test. Well its not the brightest in the world but definatly looks cool and has the shimmer effect like my metal halides. I will need to assemble one more for the other side of the tank but actually looks pretty cool when all lights are out. I have no clue as to whether or not this helps anything in the tank but hey it looks **** cool and dont need to shine a flashlight in the tank to see it at night. Total cost i figure will be less than $20 for the two sets of 4 using a 4.5VDC transformer I had from a portable cd player. Radio shack had 6VDC transformers for something like $10 that would work with about a 150ohm resistor I bet. Anyone else use these things? Hell with the flashlight reflector and the two part epoxy putty that I use to glue my frags it was **** easy and should be waterproof enough to last quite some time.