UVB light placement help

[CMHbeardie]

So newbie here. I have not gotten a dragon yet, but wanted to make sure the enclosure is set up properly before doing so. One thing that I have been confused about was the placement of the UVB lamp.
My enclosure is a 75G tank, with a screen top. I want to place the lamp on the screen top, which I know filters out quite a bit of UVB. So I was thinking of putting a 24" (22") ReptiSun T5 HO bulb with the ReptiSun HO hood (yeah, I know its expensive) over the basking area, but not over the cool side. I have seen conflicting accounts of this. Some say the bulb should span the length of the tank, and some say the cool area should be free of any UVB light. Is what I have planned acceptable for this setup?

Any help would be greatly appreciated.

 

[VenusAndSaturn]

It may work but then it would most likely be best to mount it inside with that size of bulb.
Personally in my opinion for 75 gallons, its either 34" or 46" for on top of the screen.
With a 34" bulb you also provide uvb over the middle and slightly on the cool side offering options of getting uvb without basking 24/7 for it.

I have 46" bulbs going over my 75 gallons with a cheap reflective fixture that I got off amazon that works very well, it goes diagonal across the top. I do not have a solarmeter yet but taking a guess in my juveniles tank she has about five places to go to escape UVB or get to low levels.
Two spots are underneath rocks, two more are hides/basking platforms and the fifth is a hammock on the cool area off to the side.
As for high UVB places my adult female can get within 4-5 inches away from a Arcadia 14% UVB bulb which has screen underneath it, and my juvenile can also move from her larger hammock to another smaller hammock that sits about 4-5 inches away from the same type of bulb.

Its best to provide areas without or with low levels of UVB, but you should also have areas with high UVB levels. For me I provide UVB over the whole tank, however my beardies have multiple options of UVB levels they can choose from.

 

[CMHbeardie]

Thanks! That does actually make sense to have this over the middle instead of off to one side only in the basking area.

Now I have also heard that using the HO fixtures have the correct ballasts to power those HO lamps and the use of a NO (Nominal output) fixture with an HO bulb, like under-counter fixtures bought at Home Depot, have diminished UVB output due to the under powered ballast. Any fact to this at all?

 

[3magpie3]

I've always heard that heat and UVB should overlap, and that UVB should be 2/3 of the tank... or full length of the tank is OK IF you have hides/cover so the dragon can control their temp and uvb gradients.

And yes, mount the UVB inside the screen.

Not sure about the fixtures. I have the Reptisun hood/bulb combo just because they come so highly recommended and supposedly last. I didn't want to chance anything not working perfectly. I do use a home depot fixture and halogen flood bulb for the heat lamp, though.