# T5 HO vsT8 florescent lamps



## ZEROPILOT (Jan 21, 2020)

This is my experience and first hand findings with these two types of lamps.
I'd never used T5 lighting until recently.
I've also never owned a SOLARMETER to see just how well these lights transmitted or didn't transmit UV.
For the sake of this test, ALL of these readings are THROUGH a screen cover. (The screen cover blocks out up to 50% of the UV.)
Ideally you want a reading of 3 on the scale.

T8. The type I've always used. The most common type out there.
At 4" a 5.0 puts out just 1.7.
At 4" a 10.0 puts out 3.1. Ideal. But its 4"!
At over 6" the readings drop off very sharply.
So, if you have a screen top and are using a T8. Even at just 6" the 5.0 is doing almost nothing and a 10.0 is generating a reading of about 1.
Screen tops and T8 tubes are not a good mix.


T5HO. The newest type. The type I've just been schooled on by members here and on the chameleon forum.
At 4" a 5.0 puts out 5.1
At 4" a 10.0 puts out 7.8
At 10" the 5.0 puts out an ideal 2.9
At 10" the 10.0 puts out 5+. So the light must be raised up or in the case of Chameleons, the branches must be lowered.
T5HO is ideal for placing on top of a screen top. And is the ONLY choice for having the lamp far away from your animal.

What I've learned is that a T8 can work if it is not going through screen (or plexiglass) and the animal is within 10" of the lamp. At like 7" a T8 can and will provide adequate UV.

A T5 is much more powerful and is the best choice for providing UV for animals up to 20" or more away from your fixture of it is not going through a screen. Or for those of us using a screen top. Like me. In the case of my Chameleons.


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## Markw84 (Jan 21, 2020)

That's why @Tom and I have only recommended HO T5's for some time now.

The other part of the equation you have noted, is that since UV readings increase geometrically with distance, not linerally, when you use a UVB source that has to be close to get the effective level, a little movement of just an inch towards the light can double the UVI reading. And in the same token, a little movement out from directly under the source looses any effective UV withing a few inches. By having a 12.0 HO T5 I can place my fixture at 20" and have a nice 3.0 at tortoise level. Even 4" higher it is still just 4.0 - still a good reading. AND... the zone is nice and wide giving me effective UVI readings 12" and more on either side of directly under the fixture. This is also giving nice shade basking low level UVI off under the plant cover where they prefer to rest.

If I were setting up for a chameleon, I would use the 12.0 HO T5 and have it about 8"-12" above the screen top. Then I would have a nice, broad UVI zone from 4" to 10" under the screen for branch levels and about 24" wide. I strive for basking zones not basking spots. You just can't do that with a T8 at all.


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## ZEROPILOT (Jan 21, 2020)

Thank you.
And thanks for helping to push me into T5s.
I'll be playing around with my new meter for a while.
Unfortunately I bought two replacement tubes already and they are also 6% 5.0s.

I will also recommend T5HO in the future to new members.
And suggest getting a SOLARMETER.


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## ZEROPILOT (Feb 19, 2020)

These thicker tubed fluorescents are T8.


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## ZEROPILOT (Feb 19, 2020)

These T5 are much slimmer.
These are the more powerful ones.
This one also has an excellent refector.
It's the type I currently use.


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## Blackdog1714 (Feb 19, 2020)

I love my T5 and with my Solarmeter 6.5r it is set just right. I put it on adjustabel wires so I can pull it up or down and that worked like a charm!


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## Kapidolo Farms (Feb 19, 2020)

Nice research and reporting. The digits in the T5 and T8 as well as T12 refer to 1/8 inch increment. So a T8 is one inch in diameter, a T12 in 1 1/2 inches in diameter.






T5 HO by ZooMed


I can not review the specific product, just got them yesterday. ZooMed now has T5 HO tubes in the UVB output product line. Price beats LightYourReptiles Arcadia bulbs by 30% to 50% Yeah for ZooMed to finally have this here in the US. I like the T5 HO tubes for ambient light, and watts...




tortoiseforum.org









Light Fixture


Hi All, I am toiling of what fixture and bulb to get. I am running short on time and im hoping someone can tell me frankly which fixture and bulb is best? For my RFs I want a 10.0 bulb, i know they only "need" a 5.0, but Id rather the 10.0 and be able to keep the fixture further away...




tortoiseforum.org









How to choose the light bulb?


I was using this until Iwas told that it is not good at all to my tortoises eyes: So now I am looking for a new one. Before searching online, I went to the shop. Light bulbs for reptiles were only in one of them. Like these: Are they good? And how can I know which one to choose - 50w, 75w or...




tortoiseforum.org





I've been banging this drum for a few years now. Your direct measurements ad much to the conversation.


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## ZEROPILOT (Feb 19, 2020)

Kapidolo Farms said:


> Nice research and reporting. The digits in the T5 and T8 as well as T12 refer to 1/8 inch increment. So a T8 is one inch in diameter, a T12 in 1 1/2 inches in diameter.
> 
> 
> 
> ...


Lighting has been a guessing game for me until recently.
Luckily for my tortoises they live outside!


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