ODNO 20 watt single bulb...

[Wasserpest]

In my HD they are $17.99 :P

*** Wasserpest, another ODNOholic ***

[Mini4x]

WHAT..

Around here the 4F32's are all in the $28 range..

[EvilKen]

When I measured current draw with 1x vs 2x into a single 18" bulb, it was indistinguishable. Gains are only significant when those small bulbs are put in series.

Wait, so are you saying that when I OD my 18inch 15watt T8 light 4X that it is not actually significantly brighter than a NO one? I just wired mine up yesterday and now Im wondering if there was a real increase of light, or if its just the placebo effect.

Could you please explain why OD will not work on the shorter lights?

Thanks.

[GulfCoastAquarian]

I'm not entirely sure of why OD is less effective on shorter lights. My theory is that the current limiting device is nonlinear and will compensate more strongly for low voltage drop devices (small bulbs) to protect against overheating failure.
The indistinguishable current draw was between 1x and 2x. 4x might show a noticeable increase in light, but it won't be the general doubling in intensity that you'd see with 4xODNO on larger bulbs.
Wasser, you're lucky! Home Depot seems to set their price points wherever they see fit and as luck would have it - they set it at $26 near me. That's why I don't bother with them anymore. If I'm going to spend $20 for a cheapo Advance Ballasts, I'll go on and spend $25 on a Fulham Workhorse 5 instead and have a heck of a lot more flexibility.

[Kris]

so, if i understand you all correctly, for OD to work, the tank has to be at least 4' long? mine is 24" and the hood that came with it allows for an 18" bulb.
i have been racking my brain to come up with a way to add light to my tank. i am currently running two 15 watt bulbs for 2 wpg, and the high light plants aren't making it, but the anubias is loving life.
is there a way to add light without adding hoods or spending tons of money on a new lighting sytem?
thanks,
kris

[GulfCoastAquarian]

No, Kris, you could take two 24" bulbs and put them side by side, in series. So for ODNO to be really effective, you could use it on almost any size tank, so long as you could put two bulbs side by side for tanks less than 3'-4' long.

[hooha]

any schematics for putting 2-24" in series? Right now, the light fixture I have has a 32wT8 electronic ballast in place. The ballast came with 2 "blue" wires and one "red" wire to connect to the end plates.
My endplates that came with the fixture are "coupled" already on one side (let's call it "side two"). To try to describe it, one of the endplates has 4 wires coming out of it - 2 ends are free to connect to the ballast, the other 2 wires connect to the other endplate on "side two". No other wires connect to this endplate. On "side one" each endplate has 2 wires connected that are free to connect to the ballast.

I don't want to shock myself or burn the ballast, so if anyone can confirm this is going to be the right setup it would be appreciated.

My thinking is I connect both blue wires from the ballast to one endplate on "side" one. I connect the red wire to the other endplate on "side one".

for "side 2" the endplates are already coupled, so all I need to do is "close" the free wires on the one endplate by securing them by themselves with a wire nut.

It's been a few years since my last physics class, but this sounds like 2 resistors in series....

[GulfCoastAquarian]

This is exactly like two resistors in series. By putting the resistance of each bulb in series, you are simulating a bigger load, which triggers more output from the load-sensing electronic ballast (make sure yours is electronic and not magnetic!).

There's an ODNO series diagram at the bottom of the ODNO article page. There are also several posts about ODNO in series - just use the search function to look for "ODNO Series" and you should find at least a half dozen, with pictures and all.

[hooha]

cool, it worked and i didn't shock myself

i wasn't sure if I could just twist together the "free" wires on one end or not, i guess i can

nice and bright too with the 32w ballast woohoo!