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Discussion Starter · #1 ·
1) Will typical 48" F32T8 fluorescent bulbs operate (at all) on magnetic 40 watt ballasts?:confused:

Just to run the F32T8 bulbs on magnetic ballasts for a few min, really, to compare w/similar (but lower lumen rated) F40T12's.

Not sure if running F32T8 on a 40 w ballast would effectively be ODNO bulbs by a sm amt (if they'll operate at all).

2) Also, if I decide to ODNO later (separate issue), if using an electronic ballast designed for 4 x F32T8, and IF you start out ODNO 2x for one tube, do you just cap off the two unused leads?

Thanks.
 

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As to #1, that is what I have in my garage now. I replaced the T8's over my aquarium, but the bulbs weren't dead yet. So when my garage light T12's (mag ballast - I checked) went out, I replaced them with the T8's. No problems. I assume they are getting 40 watts since the ballast is not load sensing.

Kevin
 

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Discussion Starter · #3 ·
Thanks Kevin,

Technically, I wonder what kind of increase in output running an F32T8 on a 40w ballast is producing? If anyone cares to tackle that, I'd be interested.

Seem to remember > 12 yrs ago, I ran some 48" T8's mixed w/ T12's on a 75 gal. Was long before talk about ODNO, and not much info then on different ballasts for T8 or T12.

Not sure what wattage the "Ancients" (old T8's) were, but do remember they were bright - much brighter than the T12, smaller dia. not withstanding. But bulb design of modern T-8's could've changed a lot in a decade and a half. That's why I'm asking.

IF, (and that's a big IF) T-8's today are same as yester-decade, those T-8's lasted a good 9 - 12 mo before I saw a decline in plant growth, just running them on a 40 w magnetic ballast.
 

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There might be a little bit of overdriving, but there are a lot of disadvantages to using old magnetic ballasts. Flickering bulbs (not everyone notices that), shorter lifespan of bulbs, less efficient ballast (gets hot) and others.

I would recommend going the electronic route... and yes, the unused ballast leads are just capped off (separately!) or otherwise securely insulated.

In my house, there was a 2x 40W magnetic ballast driven light. I switched out the two T12s with T8s which increased the light a little, but the flickering was very disturbing to me. Eventually I changed the ballast to an electronic one, and a single T8 overdriven by 2x is WAY brighter (and uses less energy) than both dual bulb solutions on the magnetic ballast.

The instant start of electronic ballasts is another nice feature. The blink-blink-blink of the tubes on magnetic ballasts when the starter tries to fire them is depressing to me and probably scares the heck out of your fishies. :smile:
 

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Discussion Starter · #5 ·
Thanks WaterPest,

Appreciate the feedback. I'll probably run the T8's on the magnetic ballast for a few min, just to see. The T8 rated lumens are 550 more than equiv T12 bulb (near 25% incr).
...there are a lot of disadvantages to using old magnetic ballasts. Flickering bulbs..., shorter lifespan...
I'm not suggesting using magnetic ballasts permanently for T8's. Flickering can occur w/ any ballast. May be less likely w/ electronic ballast. ODNO also shortens bulb life.
... and a single T8 overdriven by 2x is WAY brighter (and uses less energy) than both dual bulb solutions on the magnetic ballast.
Doesn't this contradict the "conventional" wisdom that ODNO2x only increases light output by approx 100%?

I'm interested in what careful considerations others have given to safety designs of DIY hoods for ODNO; Re: mounting tube receptacles (endcaps) and other fire prevention issues. Since most hoods are made of wood, seems extra precautions are in order.

I may post the last question in another thread.
 

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Before you consider ODNO, how big is your tank? Dimensions? Depth? We might be able to provide you with better solutions.
 

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Discussion Starter · #7 ·
Epicfish - FYI tank is 75 gal 48' L x 18" W.

Update / edit: Yes, the F32T8's will run on the 40w mag ballast. After 3 or 4 min, they started to flicker some (as warmed up, I guess), so shut them off. They were significantly brighter than the equiv T12 bulb.

I had an electronic ballast for 4 - F32T8 (Advance ICN-4P32-SC). Question on hooking up JUST ONE tube, in a test situation to evaluate differences in ODNO 2x, 3x, 4x:

Read lots of articles /diagrams - don't remember discussions on at what point do you start using both yell leads? Like for ODNO 2x, 3x or 4x. Or, if (for ONE bulb) you ALWAYS use both yell leads, or never, or doesn't matter. Most diagrams show a ODNO4x setup (not 2x) w/ both yell leads connected.

I'm assuming most can tell a marked progressive difference in brightness for one bulb at ODNO 2x, 3x and 4x?

Measured current using only one (red) and one yell.
Then did same w/ 2 red and one yell. Current increased - as expected. So did brightness.

Next used 2 red & 1 blue, and ONE yell to other end (3x ??). Current increased again, but can't really tell a brightness increase. Also tried 2 red & 1 blue, with both yell to other end. Couldn't tell much diff in brightness. Neither could wifey [as she stood well away as to avoid anticipated flying glass!]
 

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Thanks WaterPest,

Appreciate the feedback. I'll probably run the T8's on the magnetic ballast for a few min, just to see. The T8 rated lumens are 550 more than equiv T12 bulb (near 25% incr).

I'm not suggesting using magnetic ballasts permanently for T8's. Flickering can occur w/ any ballast. May be less likely w/ electronic ballast. ODNO also shortens bulb life.

Doesn't this contradict the "conventional" wisdom that ODNO2x only increases light output by approx 100%?

I'm interested in what careful considerations others have given to safety designs of DIY hoods for ODNO; Re: mounting tube receptacles (endcaps) and other fire prevention issues. Since most hoods are made of wood, seems extra precautions are in order.

I may post the last question in another thread.
Flickering has to do with the frequency of the ballast. Electronic ballasts run crazy high frequencies compared to the line frequency of magnetic ballasts.

Anyways...

In you PM you asked about the yellow leads... This might depend on the exact ballast that you have. The 4x Advance ballasts have yellow "Common" leads, so it doesn't make a bit of difference how many you connect to one bulb. The "hot" leads are the two blue and two red ones. These determine how much you overdrive the bulb.

Regarding fire prevention, treat ODNO bulbs like you would treat T5HO, PC or VHO bulbs. Depending on various things you might need to increase circulation in your canopy (compared to using regular T8 or T12 bulbs), if a couple of bulbs are seriously overdriven, active cooling with fan(s) would be recommended, especially if your tank tends to overheat.
 

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Discussion Starter · #9 ·
Thanks, that's about what I figured on the yellow leads (for this ballast).

However, w/o a light meter, I can't tell much difference in brightness for ea additional lead, once past 2 hot leads on one bulb (2x). But maybe it's like staring at an arc welder - after you've looked at one, everything else looks the same. Guess I can tell a difference between 2x & 4x, but not nearly as much diff as between 1x & 2x. The current draw does increase w/ each additional lead, so they're making contact.

Why's that, Mr. Wizard? I'm glad you asked, boys and girls. This is because the increase in light output for each additional step, 1x --> 2x, 2x --> 3x, 3x --> 4x, gets smaller, in what engineers like to call diminishing returns. Visually, this is the appearance to my naked eye. The venerable Shalu's own cutting edge experiments also seem to indicate the same.

His test on F32T8 showed increased light output for each step:
NO1x --> ODNO2x = 60% light output increase
2x --> 3x = 23%
3x --> 4x = only 8.5%:icon_sad:

At same time, he showed a 9.5% increase in power consumption from 3x to 4x, to achieve 8.5% increase in light. Somewhat of a diminishing return.

So, if interested in most bang for the buck, it appears one should stop at ODNO2x or 3x. If you're one that just has to see how fast she'll go, down hill... w/ a good tail wind, then go for it.

Well, that's our show for today. Tune in next time to learn how to turn your dad's lawnmower into a top fuel dragster for under $20!:bounce:
 
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