# Can I remove one bulb from a dual fixture?



## ShrimpieLove (Apr 26, 2010)

Hi everyone! 
Heres my dilemma- i have a 15 gal with an Aquatic Life dual lamp t5HO (2x24watts) and I was trying to get by on just ferts and no co2... But seems I really do need co2 for the plants at that high wattage, and Id prefer not to go with co2 right now... the plants r doing ok, but I have to dose ferts alot etc and boy do I miss my lower light setup lol
So I may decide to sell my light and get something like a normal dual tube flourescent light which would probably be 2x14 watt or so. 
Before I decide to sell it...i thought hmmm maybe I could just remove one of the bulbs in the fixture making it just 24 watt ho, i dont like to mess with electrical things so if i remove one tube is it safe to run the light that way ? 
Also, would moving the light up and maybe hanging it above the tank make it less watts per gallon?( instead of directly on the tank)


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## Harry Muscle (Mar 21, 2007)

GuppyLove said:


> Hi everyone!
> Heres my dilemma- i have a 15 gal with an Aquatic Life dual lamp t5HO (2x24watts) and I was trying to get by on just ferts and no co2... But seems I really do need co2 for the plants at that high wattage, and Id prefer not to go with co2 right now... the plants r doing ok, but I have to dose ferts alot etc and boy do I miss my lower light setup lol
> So I may decide to sell my light and get something like a normal dual tube flourescent light which would probably be 2x14 watt or so.
> Before I decide to sell it...i thought hmmm maybe I could just remove one of the bulbs in the fixture making it just 24 watt ho, i dont like to mess with electrical things so if i remove one tube is it safe to run the light that way ?
> Also, would moving the light up and maybe hanging it above the tank make it less watts per gallon?( instead of directly on the tank)


It all depends on the ballast used in the fixture. Best way to know is to try it. It will either work, flicker or not light up at alll. If it works it's most likely safe to continue running that way, that's what I plan on doing.

Raising the light will also work at reducing your light in the tank. When I have a chance I'll find a link I know of to a graph which will help you figure out exactly how high to raise it.

Thanks,
Harry


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## Harry Muscle (Mar 21, 2007)

Harry Muscle said:


> It all depends on the ballast used in the fixture. Best way to know is to try it. It will either work, flicker or not light up at alll. If it works it's most likely safe to continue running that way, that's what I plan on doing.
> 
> Raising the light will also work at reducing your light in the tank. When I have a chance I'll find a link I know of to a graph which will help you figure out exactly how high to raise it.
> 
> ...


There's one other thing you can try ... replace the second bulb with an actinic bulb. They put out very little useful light so it will lower your total light output. Just make sure you like that blue look.

Also, there's some debate as to whether actinic bulbs contribute to algae, but there's no hard proof just speculation.

Harry


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## ShrimpieLove (Apr 26, 2010)

Ohh thank u! I was going to ask how high to lift it up... Would be good to know that way I could decide if moving it and leaving the bulbs in is going to be ok, or if id need to remove one tube bulb and also move the light...


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## Harry Muscle (Mar 21, 2007)

GuppyLove said:


> Ohh thank u! I was going to ask how high to lift it up... Would be good to know that way I could decide if moving it and leaving the bulbs in is going to be ok, or if id need to remove one tube bulb and also move the light...


In case I forget or if you wanna search for it now, the graph is from a post on plantedtank.net taking abour PAR measurements, its about 3 pages long and got a few graphs in the thread. Hope this helps.

Harry


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## ShrimpieLove (Apr 26, 2010)

Thanks so much Ill take a look for it tonight


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## ShrimpieLove (Apr 26, 2010)

Would this be the graph you were talking about? 
http://www.plantedtank.net/forums/lighting/97622-par-data-selecting-t5ho-light.html


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## ShrimpieLove (Apr 26, 2010)

Interesting.... 
So going by that graph.... I have 13 inches between the bottom of my bulbs to the top of the substrate... Which would put me at about 105 micromois, but since I have 2 bulbs Id have to double the intensity which would be 210 micromois.... Which is in the reef range on that chart lol 
So if i was going for somewhere in the medium range somewhere around 60-70 micromois then Id have to have my light 30 inches above my substrate?


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## Harry Muscle (Mar 21, 2007)

GuppyLove said:


> Would this be the graph you were talking about?
> http://www.plantedtank.net/forums/lighting/97622-par-data-selecting-t5ho-light.html


That's the one.

Harry


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## ShrimpieLove (Apr 26, 2010)

That seems to be up soo high above my tank, unless i did the calculations wrong?


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## waj8 (Jun 30, 2010)

I like the first idea of removing the lamp better. Saves electricity. Most t5 HO ballasts allow you to remove a lamp and the other will still function properly. The ballasts are designed that way in case a lamp fails. Hard to say for sure though. Some fixtures use the very cheapest components.


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## bae (May 11, 2007)

You could just run the lights for fewer hours per day.


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## ShrimpieLove (Apr 26, 2010)

Which bulb would you guys suggest I try removing? The tank has lots of plants. One tube is 24 watt 6000K t5ho and the second is 24 watt 650nm t5ho(its pinkish so i think it must be like 5000k or something like that) i dont know why they list one bulbs K rating and the other in NM... Just to make it more confusing id guess lol 
The lights are on for 8 hrs a day- what is the minimum hours needed for plants?


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## waj8 (Jun 30, 2010)

650 nm corresponds to red light. Not sure what they mean by that but sounds like maybe 3000K or lower. I guess I would remove that one but hard to say. Depends on the quality of light the other lamp provides. Seems like they are intended to be used as a set maybe for growing orchids or vegetables or something like that. 

I do think that if you reduce the light in your tank that the stargrass won't survive. Sure you don't want to just try a little DIY CO2?


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## BettaBeats (Jan 14, 2010)

Hrm.. That's a nice hood. Is it 24"? or 18"? 


If it fit my 10 gal I'd trade you, I have a 24" T5 2x14W with brand new bulbs (coming Monday). I'm set up for CO2 and ferts too.

I don't know about removing a flourencent tube, if it would cause anything to happen with the circuit, or if running the fixture without a bulb would do anything?


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