I am not a "lightologist" so I can just say what I know about scorpions and how I keep them. After this, that is end of discussion for me.Michiel,
In terms of disrupting the scorpions day/night cycle, wouldn’t IR lights or ordinary red bulbs be just as bad? IR lights also emit light that is outside the IR spectrum and in the visible range. This is obvious just by looking at an IR light. When the IR bulb is turned on it produces light that we humans can see. Humans can’t see IR so therefore some of the light they produce is not IR. Wouldn’t this visible light have the same affect on scorpions as the light from any other non UV bulb that produces light in the visible spectrum? If things should be absolutely moonless for scorpions then it would seem that the only effective heating devices are those that don’t emit any light at all like heat pads, ceramic heat emitters and heat cables.
I use plain ordinary red light bulbs and heat cables to heat my enclosures...Scorpions will behave normal in this type of light and it does not disrupt their cyrcadian rythms...This means that the scorpions are still hidden most of the day and will come out at night, without being bothered by the red light.
All these UV, Moonlight, Sun-Glo, Daylight and who knows what for flashy names and crap are more for reptiles, fish, living plants, but not for our arthropod hobby. It is just irrelevant....
The sad thing is that noobs buy these lamps because people in pet shops tell them they need them, CAT-CHING!