There are lots of manufacturers that create different types of UVB bulbs with four different types have been widely known are compact fluorescent bulb, metal halide bulb, the linear fluorescent bulb, and the mercury vapor bulb.
However, there is the drawback of UVB bulbs for reptiles is that all UVB bulbs have life span. Even you get the best uvb bulb for chameleons and they still turn on and emit white light, it not means that they emit enough amount of UVB that your chamelons need. But how do you know when is the time to replace the UVB bulbs? This post is about how to test UVB bulb.
#1 UVB bulb life time
Overtime all UVB bulbs will start emitting less UVB & eventually emit no UVB. Mercury Vapor bulbs have been growing popular steadily over the past several years. This is due to their long lifespan of around 12-18 months, much longer than other types. Linear Fluorescent bulb and compact Fluorescent bulb should be replaced after every 6 months.
Because of it we all need to mark when the UV bulb was purchased so we should replace it when the time is up.
However, there is alway the case that you may how long the UVB light has been used previously and unsure what brand the bulb.
#2 How to test UVB bulb
First, you have to turn off all the bulb in the room where you place the chameleons cage, includes heating light & full spectrum light. And only turn on your UVB bulb. Make sure the UVB bulb is warmed up. Wait for about 3-5 minutes until the UVB is warm.
Using a sheet of office white paper and place under the UVB bulb. Do not place too far, the distance should be around 12-15 inches from the bulb to the paper.
If your UVB bulb is still working good and emit enough amount of UVB, the paper should show blue/purple spectrum on the white paper. On the other hands, if the paper remains only white light the bulb might be replaced or expired.
In the case if the paper shows light purple spectrum that means it’s still emitting UV but it was weaker, it is better to replace your UVB bulb.
However, this is just very simple and basic test, I would like to recommend that you should follow the bulb’s expiration date.