compare compacts, T8 and T5HO UVB sources

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compare compacts, T8 and T5HO UVB sources

Postby kingofnobbys » Tue Aug 08, 2017 5:38 am


Naked globe or tube

example calculation for comparing a 10%UVB T8 with a 12%UVB T8 tube :
assume the curve for the 10% T8 is the 12% T8 curve shifted to the left by a factor of 1/6 ,
aim for a flux of 180 to 200 microW UVB / at the basking spot.

Assuming the T8 tube is in a reflector hood and mounted so nothing is obstructing the UV (ie under the mesh lid)

example calculation for a 10%UVB T8 tube , take the 12%UVB T8 curve
read off 200 microW UVB / for the 12%UVB T8 ==> 14cm for the 12%UVB T8
adjust for the reduced power of the 10% tube by a factor 1/6 ==> 14cm x (1-1/6) = 14cm x 5/6 = 11.6cm

read off 180 microW UVB / for the 12%UVB T8 ==> 15cm
repeat adjustment ==> 12.5cm for a 10%UVB T8 .

So the basking spot needs to be between 11.6cm and 12.5cm from the bottom of 10%UVB T8 tube to provide 180 to 200 microW UVB / at the basking spot when the tube is in a reflector hood and mounted UNDER the mesh lid.
That's 4.6" to 4.9" for you americans who don't understand metric SI measurements.

with reflector (hoods/domes) to focus UV :

Arcadia 100W MVB performance

Added (10jul2018) information on MegaRay MVB 100W and 160W - ... st-results

Note effect of mesh lids in attenuating the UVA & UVB flux received at the basking spot : will cut UV by at least 28% == I recommend mounting UVB globes and tubes UNDER the lid.


Data drawn from UV Guide :
so if ontop of a mesh
if it's fine mesh, you need to compensate for the 38% loss ,
so the correct distance is X = (1-0.38)x ,
ie Arcadia T5HO 12%UVB in a reflector hood is x = 27cm , so X=(1-0.38)*27 = 16.7cm

Stylised optimal lamp plan view of layout of basking and UV tube (and hood).

Example , simple / cheap way to double UV :
move the UVB & it's reflector hood UNDER the mesh , that's going to bring it 2 - 3 inches closer which will help in 2 ways :
>>> no mesh between him and the UVB so no shading of the UV , this will increase the UV by 30% (4mm mesh) - 40% (flyscreen) , let M = 1.4 (on removing mesh)
>>> 2 - 3 inches closer can result in a 25-30% increase in the microW UVA and UVB / , let D = increase moved 3in close = 1.3

ie increase = M x D = 1.4 x 1.3 = 1.82 x increase - just under double the UV with two simple changes.

VitD3 fortified calcium is not necessary if the photoperiod is long (15 - 16 hrs) and lights are deployed at a distance to provide 180-200 microW UVB / at the basking spot and 70-90 microW UVB / elsewhere.


Not all UVB compacts, tubes and MVBs are created equal - or are as well made.

Many Chain Petshops sell their own brand (AND CLAIM these are just as good as the more expensive UV sources)

Bands to DEFINITELY ADVOID buying are as follows :
Nomoy Pet,
All Living Things,
MegaRay Brand,
Nat Geo ,
Sparkzoo reptispar,
Repti-Zoo ,
Natural Selections (in green boxes) .

All of which are cheap Chinese clones made very cheaply using very poor quality quartz glass and cheap phosphors and next to no quality control or no meaningful quality control ==> very poor UV spectrum produced including UVC and bad parts of the UVB band --- these will harm your pet.

>>> domestic fittings for T8 and T5 tubes are fine PROVIDED the tube is not covered == the cover will stop all UV.
>>> a slip on reflector or use of a reflector hood is an excellent investment as it will focus and essentially double the UVA and UVB seen by the beardie , and no UVA or UVB will be wasted by radiating to areas inaccessible to the beardie
CBDs: Cleopatra & Caesar born 28Jan19.
Puff (RIP 10Dec15),Rex (RIP 16Mar17),Toothless (RIP 26Nov17).Peppa (RIP 22Mar19).
EBTSs : George & Mildred (born july 2010).
EWSs : , Fluffy (F) rescued injured by lawnwacker 14Nov17, Gutzy (F) rescued 27Sep19 - RIP 3Aug20 (est 12 yo), Wriggles (F) - injured rescue, over 8 yrs old, RIP 2Feb16 old age. Lucky juvenile (M) - cat attack rescue (lost r-eye, broken r-lower jaw), fatal SI RIP 21Jul2010.
kingofnobbys Sicko
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