My wifes advisor has a shelf of 3 gallon pico tanks they used to use in a class but now are just gathering dust, so we decided to use one as a pico reef in her lab. Originally we used 2 of the 9w lights for it, but they are crappy, they rust and fall apart, and they get REALLY hot. The tank has been setup for about a year probably, it has not been maintained for crap really. It has only ever had one water change, and that was because 3/4 gallon of kalk water got dumped in and overflowed out... We sometimes dont come in for a week or two at a time, and it is just treated badly all over. I recently realized the 2x9w lights have actually just been on 24/7 for god only know how long, at least 1.5 months though. I decided to build and LED light and will eventually do an ATO as well when the float valves come in. I am a student, so the budget is always tight. I got 8 violet LEDs for a $3.32 shipped bid on ebay and had a pair of 3w 2700k warm white luxeons from steeves LEDs that I recycled from an old algae growth bucket, I stuck them on an old CPU heatsink with a $8 ebay driver. So out of pocket this was ~$12, plus what I had laying around because I am a cheapo packrat. This light is almost all ~420/660nm with almost nothing in blue range, should be interesting to see how the critters do with just the Chlorophyll A band being covered.