Hi, when I first started keeping my baby tortoise I purchased a full spectrum UVA+UVB vapor lamp. a replacement after that & it served me fine at first but now my tortoises are taken outdoors for natural sunlight at temperatures of 22-28 degrees celcius 4-5 times per week or in the summer time often above 30 degrees. Is it even necessary to buy UVB lamps alone when UVA for heat source is sufficient? I find full spectrum lamps are over rated & expensive than if bought separately, half an hour of natural none filtered sunlight equals 8 hours of artificial UVB.