Ha...thanks Tom. I understand the importance of sunlight and I try to get the little one out as much as possible. Since I work during the day I cannot always get him out in the sun though. And in the winter I will not be putting the little one out either.
From my experience MVB's say to change every 6 to 12 months. That seems kinda generic especially since you may get a bad bulb that burns out quickly. Since MVBs are my torts main source of UV at this point, I would like to know how much UV the bulb is giving off and make sure it is sufficient.
If anyone has any experience with the UV output of MVBs I would appreciate it.
If you get a good brand like a T-Rex Active UV Heat or a Mega Ray, they have done so much testing plus this site has: http://www.uvguide.co.uk/mercuryvapourlamps.htm, that the 12 months is supposed to be a very conservative number. UV meters are very expensive, but sometimes a reptile club or vet will have one for you to borrow. If you can get the tort out on a regular basis for sun, such as 30-60 minutes more days than not, then that is likely sufficient and you don't need the bulb. Some people will just use the bulbs in cooler months since they have their torts outside in the warmer months, so the bulbs will last longer (only the time they are on, assuming about 12 hours a day, counts). If you are buying a good quality MVB, you shouldn't get a bad one that decays quicker. Sometimes they will die before 12 months though...so far I had one go out at 9 months and one at 10...out of two bulbs. Third one is a few months in so far. Using a UVB meter, you'd look at the data for the bulb and see the useful range, and then if the bulb measures below that at the substrate level where the tort is, then you'd want to replace the bulb. Bulbs rapdily decay from the time you turn them on such that at 12 months they put out like half or less then when you bought it, but its still sufficient, especially when the tort basks for longer. Even at 12 months old the MVBs put out more than a new tube UVB.