# T12 bulbs burning out after a couple of weeks



## CatG (Apr 10, 2010)

Hello,
I set up my tank a little over 3 weeks ago, and am having problems with my lights. I am using GE brand F40T12 lights, and have had two of them burn out so far. I have them all mounted in a regular el cheapo flourescent fixture from Lowes. Could that be the problem? Do I need some sort of special fixture? They all came from the same store, so maybe they got in a bad batch? Not sure what's happening here.

Any advice is appreciated!
Thanks,
Cat

PS. They are on maybe 8 to 10 hours a day.


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## Big_Fish (Mar 10, 2010)

Hi, CatG.. 
Maybe a silly question, but are you SURE the problem is that the bulbs have burned out? 
I'd confirm by swapping the bulbs around to make sure the problem follows the bulb, and not the fixture.


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## Cliff Mayes (Jan 29, 2007)

Take everything back and get new stuff. They should not burn out that fast. The suggested ritual is a good one but if they have been OK up until now the problem is probably either the bulbs or ballast and neither one is your problem although putting the fixture on a tank could have led to the premature failure.


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## CRS Fan (Nov 25, 2008)

As inferred above, it sounds like a ballast issue to me.

Good luck,

Stuart


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## CatG (Apr 10, 2010)

Thanks for the replies!

The bulbs are definitely burnt out, as they have turned black at the ends.

I am very new to this, and I don't know what a ballast is. I will look it up to see if I can find some info.

Thanks again,
Cat


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## Seattle_Aquarist (Mar 7, 2008)

Hi CatG,

Are you sure the fixture is for T12 and not T8 bulbs? Some fixtures do both types, some do not.


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## CatG (Apr 10, 2010)

I did some checking, and I was able to find the ballasts themselves, and instructions on how to replace them if they go bad. However, I doubt the ballasts are bad as I bought the fixtures 3 weeks ago when I bought the bulbs.

On the other hand, I _think_ both dead bulbs were in the same fixture. My hubby replaced the first one, but I'm not entirely sure which fixture it was in. If they were both from the same one, the fixture may be defective. I will ask him when he gets home.

How do you check to see if the fixture is rated for T12's or not? Will that info be printed on the ballast label?

If I find out it's not rated for T12's, then that is probably my problem. I will check that first, and then move on from there.

Thanks,
Cat


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## CatG (Apr 10, 2010)

I've got another quick question about my setup - I have 4 of these bulbs (4x40 watt T12) mounted over my 75 gallon long tank (about 19" tall from lid to bottom). The bottom of the bulbs are about 8.5" above the glass top of the tank. Are these mounted at about the right height? Is that enough light for moderate light plants?

Thanks, and again, sorry for all the questions. 
Cat


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## Newt (Apr 1, 2004)

The ballast in shop lights usually say right on them what bulbs they will drive. If they have blackened at the ends this means the cathode is kaput. If the ballast was meant for T8 size bulbs I doubt the T12 would light up properly. They would have light 'rolling' and flickering along the length of the tube. 
I doubt a T8 ballast could burn out a T12 as a T12 takes more power to operate it.
Bad bulbs and/or ballast.


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## CatG (Apr 10, 2010)

Well, I found out that both burnt out bulbs came from the same fixture, but the fixtures also say they are for T8's, with no mention of T12's to be found. Since both came from the same fixture, I would guess that fixture is bad, but I am going to try to find T12 fixtures and replace them both.

Thanks for the help!
Cat


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## Seattle_Aquarist (Mar 7, 2008)

Seattle_Aquarist said:


> Hi CatG,
> 
> Are you sure the fixture is for T12 and not T8 bulbs? Some fixtures do both types, some do not.


Hi CatG,

The only reason I suspected the compatibility is I made the same mistake myself once! LOL


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## joshvito (Apr 6, 2009)

> Well, I found out that both burnt out bulbs came from the same fixture, but the fixtures also say they are for T8's, with no mention of T12's to be found. Since both came from the same fixture, I would guess that fixture is bad, but I am going to try to find T12 fixtures and replace them both.


IMO, T8's are better than T12's. T8 are more efficient, especially if the ballast is electronic. If the 3 week old fixture you bought is bad, I would return for another T8 and get the correct T8 bulbs to match.

A side note; the home depot by me sells $8 4' T12 shop fixtures with electronic balasts. I run T8's in the fixture for periods of 9 months or more. The bulb runs slightly hotter and brighter, but no hotter than my T5HO fixtures. A setup like this will shorten the life of the bulb, but not affect the ballast. The energy consumption is the same as running T12's though.


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## Newt (Apr 1, 2004)

Hhummmmm, underpowered T12s. This has peaked my curiosity. I'm going to setup a ballast for T8 and plug in some T12s and see what happens.

CatG: Are your ballasts electronic or magnetic?


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## Diana K (Dec 20, 2007)

If you can post the 'alphabet soup' on the balast that might help. Balasts are labeled with a series of letters and numbers that might be translated to what it is and what it can handle. 
Is there a brand name on it?


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## CatG (Apr 10, 2010)

I'm not sure about the ballasts. Tomorrow, I will see if I can find the info and get back to you.

As for using the T8's, I would love to, but I don't think the stores around here sell them. Maybe the LFS will have them, but if they do, I bet they are overpriced. I will check and see, because then all I have to do is buy new bulbs. We riveted the two fixtures together to make essentially one fixture, so I can't take those back. 

Thanks,
Cat


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## Newt (Apr 1, 2004)

Lowes and HomeDepot and Walmart all carry T8 bulbs. They are thinner than the T12. 
1" in diameter instead of 1.5"

Really interested in the ballast type so I can run a test.


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## CatG (Apr 10, 2010)

Thanks! I will check there and see what they have. Will they be labeled as plant and aquarium bulbs, or do I get just any old T8? Are there any specs I should be looking for, other than wattage?

I will get the info on the ballasts. I am quite familiar with needing info for an experiment, so I would be happy to get it for you. Unfortunately for me, my info for my experiments usually needs to come from museum curators in foreign countries, and it ain't easy gettin' info from them. lol

Cat


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## Seattle_Aquarist (Mar 7, 2008)

Hi CatG,

Newt seems to have disappeared. I use "Daylight" type bulbs rated about 6500K to 6700K if possible.


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## Cliff Mayes (Jan 29, 2007)

As a quick tutorial, that will probably bore the older hands, please accept the following information.

At one time, and just as everything else, flo light got changed. T12s got changed to T8s and now to T5s and the ballasts that once were large, heavy, black, metal boxes inside a flo light that allowed the Flo light to get up to running power became electronic and used a lot less power and generated a lot less heat, or wasted energy. The T12s were one and a quarter inches and the T8s were just an inch so the number referred to 1/8th of an inch. LEDs will be the next big deal as soon as they get perfected and the price comes down.

This Hobby is large but has never generated the experimental evidence that other industries have so we just sponge off of others and use anecdotal evidence to determine right and wrong. At one time, not very long ago, there was only one reference that had a lot of information, some of it not so good, but got passed along as of it were absolutely so.

About 30 years ago the Europeans showed us how to put a lot more light over a tank. To be sure there are still a lot of folk that still buy a ten or fifty-five with one or two flo lights or incandescents on them and wonder why they cannot grow plants similar to what they see on the Net. The amount of light available outdoors is incredible compared to what we put on our tanks.

Incidentally information on the Net has been very good but everything on the Net is not good. It is just a easy to claim sex, age, and background that is incorrect as it is to state the truth so just wait a few days till someone gets on to dispute the info or at least allow info to "stew" for a bit before acting on it. The NET has been wonderful as far as allowing knowledgeable sources to exchange or pass on info that they have accumulated and have some need to pass on but there are not any devices to assure that you are getting the truth.


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## CatG (Apr 10, 2010)

Thanks for the info and the advice! I appreciate it!

I have the info on the light fixtures. The brand is UtiliTech, model number NXU-6000 EBL. It takes two 32w T8 bi-pin linear bulbs. The ballast is electronic. This info came from the box. If you need info printed on the ballast, let me know and I will take the fixtures down and check.

Cat


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## Newt (Apr 1, 2004)

Thanks for the info CatG.
I'll hook up a set later today.


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## Newt (Apr 1, 2004)

Well I have an Advance ballast that runs 2 T8s in my collection of lighting stuff so I hooked it up to a six month old used Sylvania GroLux Std and a Wide Spectrum. To my surprise they lit up without any rolling or flickering. Being GroLux bulbs for plants (low lumens = low green emissions = deim to begin with) it was difficult to tell if they were dimmer than normal - plus being 6 mos old they have dimmed by approx 60%. I didnt have any other used GroLux so I didnt bother to hook up any to a ballast that will drive T12s to compare. I would have to say they were dimmer from being under-powered.


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