My cheap diy moonlights
Roaming all the local electronic places, the only white LED's I could find were 6cd, and $5. Frustrated, I looked at the dollar store. They had Dual white LEDs in a diffuser, for cabinet lighting (and 3 freLR44's for your digital thermometers).
Used a wall wart for power, put all the resistors on a board and then added a pot so I could dim it. I plan on mounting these underneath the front rim.. The biggest problem I've been having with moonlight experiments, is that you get glare from the bulb, underneath the front rim you don't see the lightsource.
On a previous moonlight experiment, we discovered a neat effect when it broke. An LED on the bottom of the tank was pointing up from the middle. It made a neat projection onto the ceiling. The light made a lava lamp type effect on the ceiling with the HOB surface disturbances which was quite pleasant. I'm going to mount an LED onto a skewer, and hide it in my gravel/carpet plants, so I can have this effect on a switch, yet somewhat hidden when not in used.
I'm using copper wire, and keep shrimp, so this is a picture I took while the silicone waterproofing was drying. Will update when it's installed.