The blue light you see in the tanks is actually called actinic lighting....It is neither black light or lunar lights.
And yes LED
moon lights are expensive....15$ a peice is not uncommon for blue LEDs.
And lunar lights only come on at night!
And Actinic lights are even more expensive, you have to buy a ballast and have a hood to mount it in, and you also need a 10,000K daylight to go along with it.
The best way to go for most people is to buy a hood from Coralife or Current USA. Check out Hellolights.com!