if you want to diy it, www.ledsupply.com has blues that are 470nm. They also have lamp drivers so you won't need resistors and anything else you need to make them work. I strung 24 of them and connected them to a dimmer so I can adjust the brightness to the actual moon phase. Warning: LED Supply are very inexperienced with aquarium application, but overwhelminly good with the tech end of their business... gets a little confusing talking to them if you don't know exactly what you want.