SpacialCoogs
Sub-Adult Member
Coil bulbs only produce UVB in one spot of the tank instead of the whole length of the tank. In an artificial setting for captive animals, you'll want the UVB to span about 2/3 of the tank as UVB bulbs are weaker than radiation from the sun, so the animals need to be exposed to more of it to compensate for that. Coil bulbs also produce an unreliable amount of UVB because of the way they are shaped and the UV wavelength they output is shorter than in strip lights, making them harsh, and can cause photo-keratitis, which is severe eye damage.
This is a great explanation. I will steal this to help others if you don't mind.