# removed one bulb, still the same intensity ?



## eminor (18 Oct 2021)

Hello, i have a 2*24w t5ho odyssea fixture, with a kind of parabolic reflector, I removed 1 bulb, the light seems to be the same intensity as before, how is that possible, are my eyes playing with me ? thx


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## MichaelJ (19 Oct 2021)

Just an idea; depending on the fixture, you might experience that when the two tubes are in, and if sitting close to each other, they tends to shade each other, so when you remove one bulb you might not see a reduction by half the output as you would expect.


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## ceg4048 (19 Oct 2021)

eminor said:


> Hello, i have a 2*24w t5ho odyssea fixture, with a kind of parabolic reflector, I removed 1 bulb, the light seems to be the same intensity as before, how is that possible, are my eyes playing with me ? thx


Correct. Plants do not have eyes, they have mechanisms that operate using quantum electrodynamics and cannot be fooled.
These mechanisms respond to the rate and quantity of photon bombardment per unit area. This is called "Photon Flux Density". Each chlorophyll molecule is exposed to this bombardment and due to the number of "torpedos" raining down there is a certain probability that the torpedo will hit the right spot.
Two bulbs produce twice as many photons as one bulb does and therefore, the bombardment is twice as intense. The probability of a torpedo hitting the right spot is therefore twice as high.

Your eyes have pupils which open or close, depending on the number of those same torpedos. When the rate of torpedo bombardment is twice as high your pupils may respond by reducing the diameter to allow fewer torpedos to enter. When the rate is lower the pupil may open wider to allow more to enter. The number of photon torpedos striking your optic nerve is therefore modulated by the pupil diameter.

Lacking pupils, plants must find other imaginative ways to protect themselves from intense photonic bombardments. They don't always succeed however...

Cheers,


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## MichaelJ (20 Oct 2021)

ceg4048 said:


> Your eyes have pupils which open or close, depending on the number of those same torpedos. When the rate of torpedo bombardment is twice as high your pupils may respond by reducing the diameter to allow fewer torpedos to enter. When the rate is lower the pupil may open wider to allow more to enter. The number of photon torpedos striking your optic nerve is therefore modulated by the pupil diameter.


Hi @ceg4048 True. While I could definitely tell if I had a burned out tube back in the day when I used  fixtures with two or more T5 tubes over my tanks, the difference was not as discernible to my eyes as I would expect, which probably is attributed to  adaptation. 

Cheers,
Michael


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## eminor (30 Oct 2021)

thx, another question, can i mix t5no with t5ho in a t5ho fixture ? thx


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## oreo57 (30 Oct 2021)

eminor said:


> thx, another question, can i mix t5no with t5ho in a t5ho fixture ? thx


The ho ballast will over drive the no bulb.
Reported to work but shortens the bulbs lifespan.
Never seen it as err " recommended".


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## eminor (30 Oct 2021)

oreo57 said:


> The ho ballast will over drive the no bulb.
> Reported to work but shortens the bulbs lifespan.
> Never seen it as err " recommended".


overdrive mean the light output will be the same as ho ?

i don't mind the reduced lifespan because they are so cheap, is there any other risk ? thx


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## oreo57 (31 Oct 2021)

eminor said:


> overdrive mean the light output will be the same as ho ?
> 
> i don't mind the reduced lifespan because they are so cheap, is there any other risk ? thx


It will he more but not sure it translates to equal as a ho designed for the output current.
Probably some spectrum shift as well.
Bit more regarding heat.









						Can regular T5 bulbs be used in T5HO fixtures?
					

I want to buy a nice 48" t5 ho fixture that has 4 54 watt bulbs and replace one of them with a uva/uvb reptile bulb. The problem is i cant find any uva/uvb t5 HO bulbs, i can only find 48" 28 watt t5 normal bulbs, so can i use regular T5 bulbs in my T5HO fixture? Thanks!




					www.dendroboard.com
				




Keep in mind I've never done this personally sooo
YMMV


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## eminor (31 Oct 2021)

oreo57 said:


> It will he more but not sure it translates to equal as a ho designed for the output current.
> Probably some spectrum shift as well.
> Bit more regarding heat.
> 
> ...


thx, i will and i'm gonna update that topic every few months in case anybody want to know


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## eminor (27 Mar 2022)

update after few months, bulb is still going strong =)


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