T8 Reptisun 5.0 or 10.0 in DIY vivarium?

I'm in the process of building a three tier stackable enclosure. The bottom will be for breeding dubias (but for now the dragons) and the middle and top for the beardies.

I know what dimensions I prefer. I'm just trying to fine tune my blueprints.... IF the bottom of the uvb light fixture is 15 inches from the bottom and 6 inches from the basking (given that at this point I can still plan to move it further from the basking area) would a *T8 Linear Desert 5.0 Reptisun Fluorescent Bulb* which claims to have a healthy 12"-7" radius ORRR the *T8 Linear Desert 10.0 Reptisun Fluorescent Bulb* which claims 18"-10" be a healthier option?

Now it will be on the inside of the terrarium, so no screen blocking it, and the fixture will have a reflector. I'm afraid that the 5.0 would be plenty for the basking but not enough for the "hot" side. On the other hand, I am afraid that the 10.0 would be good on the "hot" side but too much for the basking.

I could move the fixture away from the basking area if using the 10.0. But how much? And, I will also have elevated walking areas and stuff to climb on. So, would that give enough uvb to use the 5.0?

Are you sure that 10.0, which is what you need, is a t8 bulb? That sounds like the range of a t5 high output

Update: you need a reptisun 10.0 t8 bulb for that. Another point is length, you want it about 3/4 to 1/2 the length to give cooler shady spots

ancapper":vftarg72 said:

Are you sure that 10.0, which is what you need, is a t8 bulb? That sounds like the range of a t5 high output

Update: you need a reptisun 10.0 t8 bulb for that. Another point is length, you want it about 3/4 to 1/2 the length to give cooler shady spots

Click to expand...

Thanks. I have already decided my length and a T5 would be much to intense for a depth of 15 inches. Why, may I ask, do you suggest the 10.0. My elevated areas will be between 3 to 6 inches high with a climbing area spanning an area of the back. My phone is hateful and doesn't agree with posting pictures or I could give you a much better picture but it is a corner habitat. Apartment life limits room.. If you can Imagine a diamond shaped habitat, front to back corner is 3.5feet, left corner to right corner is 5feet. I'm keeping the right sides the hot side, with their uvb's and higher wattage halogen, and the cool side with a low wattage halogen. The back area will have a ceramic heat emitter for night (as we keep our house very cool at night)

This may help you understand the difference and select a lamp accordingly.
https://sites.google.com/site/thelizardmadness/lighting-guides

The 5.0 is to weak for a bearded dragon, and the further away the lamp the better, rather than trying to minimize the output of the lamp for a small distance.

Taterbug":3m54ahw7 said:

This may help you understand the difference and select a lamp accordingly.
https://sites.google.com/site/thelizardmadness/lighting-guides

The 5.0 is to weak for a bearded dragon, and the further away the lamp the better, rather than trying to minimize the output of the lamp for a small distance.

Click to expand...

From left to right, on the no screen chart, the 14th down, in black (not blue), Reptisun10.0(1). I'm really sorry but I don't understand the key to decifer the light fixture combinations. Can you help with that, please? What fixture and is this one a t8 or t5? It would be perfect according to the uvb readings listed under it.