UVB Lighting Question

Hi, this may turn out to be a stupid question but maybe someone out there can help me.

Because of the restraints I originally had for the positioning of lighting in the roof of my terrarium I purchased 2 ZooMed Reptisun T5 HO 30cm (12") 15W TL Hoods thinking this would give the same level of UVB as a single 60cm (24") hood.

But now I see that the TL lamps that go in the 60cms (24") hoods are rated at 24W output so is my setup giving only half the UVB I require?

So, 15W + 15W does not give 30w but just 15w over a wider area?

You may confirm that I've been an ***** !
Thanks

Hi there,

UV doesn't really add to itself like that. So using 2 bulbs, doesn't make the UV exposure twice as strong as 1 bulb. What it does, is it just spreads that strength over a larger distance.

So are you running the 2 12s longitudinal? If so, that's essentially the same thing as using the 22 inch version of the T5 (covers a longer distance)
For instance, the 12 inch T5 will provide a UVI level of around 3 at a distance of 15 inches just the same as the 22 inch bulb or the 34 inch bulb.

What size tank do you have?

-Brandon

Thanks for the reply, yeah I'm running the 2 12s longitudinal down the terrarium.

Sorry had a brain fade for a moment of course the 15W for the 12s and the 24W for the 24 inch versions only defines the power used by the bulbs but the output will be the same for both.

I was just worried my dragon might not be getting sufficient UVB.

You asked terrarium size, here are some details:



We have an all glass terrarium with inbuilt 3D rock from local terrarium/reptile specialist.

It is 100cms X 50cms X 40cms although because of the inbuilt 3D rock structure the actual depth is around 30cms.

The inbuilt rock structure has 3 levels at the left and right hand sides but on the right the middle level is lower.

Left Top level is 10cms from heat lamp and 20cms from UV TL (temps are 42°- 44°C)
Left Middle level is 25cms from heat and UV TL (temps are 32°-41°C)
Left Lower level is 50cms from heat and UV TL (temps are 25°C)

Right Top level is 15cms from UV TL (temps are 27°C)
Right Middle level is 40cms from UV TL (temps are 25°C)
Right Lower level is 50cms from UV TL (temps are 24°C)

Temps taken with IR temperature gun and checked against known reference.

The 2 Reptisun lamps T5 HO 10% do not have a mesh in front of them and at the nearest point are about 25/30cms from main basking spot.

The resident is a 1 year old Pagona Henrylawsoni, named "Henry".

Thanks Again
Regards