I have blue leds on my Coralife 72" deluxe lights for my 125 gallon (473 liter) tank. They give a nice effect. I have 2 Coralife leds that I put on a 20 gallon long tank and they do not look as nice. The reason is the blue leds on the 20 gallon long give a spot light effect, since the tank height is lower at 12" high, compared to my 125 gallon tank, which is 22" high, even thought the 125 gallon has about 5 leds and the 20 gallon long only has 2 leds. There are some DIY info regarding using cold cathode light tubes used on computers for moonlighting effect. This type of lighting spreads out more and gives a nicer look. Some DIY info has a variable power control, so you can adjust the intensity of the light. Otherwise, the light will be to bright and will not really look like a moon lighting, but just regular daylights with blue spectrum.