How often should I change bulbs.


May 6, 2020
Location (City and/or State)
So I have had my combo uv/heat halid bulb for about 11 months. Should I change it out and buy a new one after every year. Or 2 years. I am not sure at all and I know they are expensive so I do not want to buy one if I do not need one. Any advice would be appreciated.


Well-Known Member
5 Year Member
Platinum Tortoise Club
Jan 17, 2012
Location (City and/or State)
Sacramento, CA (Central Valley)
There is no way to know unless you have a solarmeter to check it. It will continue to put out light while the UV portion of the spectrum has degraded and not longer is putting out enough UVB. You cannot see or tell the difference without checking with a meter. I do not have specific personal experience with the halide bulbs. They are reputed to last longer than Mercury Vapor bulbs in producing UVB and I see claims of up to 2 years. However, I see the same claims stating Mercury Vapor Bulbs last up to 1 year and by measurement we have found that most often not the case at all. My bulbs of choice are the HO T5 fluorescent tubes. I get at least 2 years out of all my tubes and still have good UVB levels by meter check.

So there really is no way to know without a meter. In the long run, it will save you money by not replacing expensive bulbs unnecessarily. OR help your tortoise by changing sooner when you know the UVB has dropped. I feel it is best to KNOW what UVB levels are for the health of my tortoise. I would never have an enclosure without good thermometers and hygrometers! We are finding proper light is just as important as temperature and humidity.