I have an AW UVC 9W light bulb and I’m not quite sure if this is the right lighting for my red eared slider. The bulb can be put underwater to prevent any harm to the eyes or skin. Will this UVC light be harmful for my turtle or is it just like the UVB light for basking?
First a little about the difference of UVC versus UVB light. UVB is what makes us tanned and causes sunburn if overexposed, but we need the UVB to synthesize vitamin D3 in our skin (source: Wikipedia).
UVC is light with a shorter wavelength and it will therefore penetrate deeper into the skin and this might cause skin cancer, damage to the eyes and severe skin burns - which are not the same as sunburn, they occur deeper in the skin and are therefore more dangerous.
UVC is used by water suppliers to kill bacteria and viruses, it works by killing or inactivating pathogenic microorganisms (sterilizing) so they are unable to reproduce and perform vital cellular functions. UVC is also used on fish tanks, garden ponds and in commercial fish farming to lower the amount of bacteria, algae, viruses and parasites in the water.
UVC is used to sterilize surgical equipment at your doctor's office, at the dentist and in hospitals.
So DO NOT USE UVC LIGHT on any animal or plant, and be careful when you use UVB on your turtle: a little UVB is good, but a lot of UVB can be harmful.
UVC is not for basking.
UVB light allows the metabolism of your turtle to work correctly. UVC light is used to kill germs, and does not even naturally occur below the tropopause of the atmosphere.
So they are totally different lights, you will need an UVB lamp.
Also see the Wikipedia article for more details :).