Join Date: Jan 2004
Location: Vancouver, Canada
Your electrician probably had the same problems with ODNO as I did. It's not a "legitimate" lighting approach - it's really more of a sneaky exploit of electronic ballast design.
You know why you can put any bulb from 1W to 54W into a 54W ballast? It's because the ballast is load sensing. In an electronic ballast this is detected and the current is "sent" based on the load detected. Most electronic ballasts allow you to hook up 2 or 4 bulbs by providing multiple outputs. If you wanted to run a 100W bulb on a 4x54W ballast, it can be done, but you would need to combine two of the 54W outputs into one bulb to get the requisite power draw (or else the ballast would either fry itself or it wouldn't be able to fire it in the first place, depending on how much excess wattage is called for).
So what happens when you combine two outputs on a bulb that can be run by a SINGLE output? Each lead that is hooked up will sense the bulb's power rating. Both of them say "ah, a 40W bulb, I need to push 40W" and now that bulb is effectively an 80W bulb. The result is that you get roughly 170% light output (for wider fluoro bulbs - IME it works like crap on T5s) and correspondingly a lot more heat output. If you can keep it chilled (or just well ventilated - fans may not even be necessary) you've basically exploited that ballast's functionality in order to get more juice through the bulb.
Try it, it works. I'm a bit dubious of the 1.7x output that has been reported, but if you run two bulbs side by side, the ODNO one certainly looks a bit brighter.
/me goes to buy a cheap light meter, too.
77 gal fresh: South Americans + plants w/ 4xT5 NO
65 gal reef: Nothin' w/ 4xT5 NO
33 gal brackish: Gobies w/ 1xT12 NO