Introduction to UV Lighting

Written by Tracie Kretzschmar, MS in February, 2008
Last updated: December, 2009

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Choosing lamps

Non-UVB lamps

Our goal should be to simulate the natural daylight or sunlight spectrum as much as possible.

I encourage the use of halogen lights when the proper wattage is used for the correct size of tank. They are incredibly bright and hot for basking. They do tend to put out a lot of heat so caution should be used with them and normally should not be used in tanks smaller than a 20 gallon.

Ideally, they should be controlled by a dimming thermostat, for safety. The natural daylight household bulbs that are of a bluish color should not be used due to their Neodymium coating which dulls the hues for the reptiles. It appears brighter to our eyes, but not to the reptile's eyes. The Neodymium is a coating that is put on to increase the color rendering index falsely giving it a perception of a brighter light but to reptiles, it blocks out the yellow hue on the light spectrum which is important for their activity. A regular household lightbulb is fine to use however, as they are very bright & do not have any coating on them like the daylight bulbs do. The Kelvin readings or color temperature for regular household light bulbs are relatively high.

The natural daylight fluorescent coils and the natural daylight fluorescent tubes are safe to use, put out little to no heat but will greatly increase the overall brightness of the tank.

So, it does take a good amount of planning to determine what type of lighting will best suit the setup that you will be using.

None of these daylight lamps produce UVB, though.

UVB Lamps

There are several types of UVB lamp available to the consumer today. There are fluorescent tube bulbs, coil and compact lights and mercury vapor bulbs. The particular brands will not be discussed due to the lighting industry constantly revolving and changing and hopefully the standards will be improving. I will recommend that you read Frances Baines' article at the end of this discussion in conjunction with this article to study the brands of lamp, and which ones are not good and which ones are. She has so generously spent her time with me helping me with technical knowledge and learning. Her countless hours of testing, research, and writing reports do not go unnoticed and her expertise is incredible.

Here is just a little bit more on UVB lighting in general. The fluorescent tubes are generally speaking, lower UVB output bulbs and do not generate much visible light or heat at all, so a bright white basking light must be used in conjunction with a fluorescent tube UVB to enhance the full spectrum of lighting and heating for your reptile. It is also recommended that while the tube may continue to come on for well over a year, that doesn't necessarily mean that it is emitting usable UVB rays. Unless you are using a UVB meter and know exactly what the bulb is putting out it is best to replace a tube bulb of a good brand after 6 or so months for maximum output. The flourescent tube bulbs should not be placed any closer than 6 inches for safety as well. They should run 3/4ths of the length of the tank with the basking light very close to the tube, on one side of the tank so that the reptile gets UVB at the same time it is basking.

Mercury vapor bulbs are high-end lamps; good quality ones produce heat, light and high UVB. Normally most types produce enough heat just by themselves without any supplemental heating depending on the size of the tank and your setup or the time of year as well. It is recommended to use a bright white daytime non-UVB fluorescent tube or coil just to enhance the overall brightness without adding any additional heat. It is also noted that it is best not to use a mercury vapor bulb in tanks under 40 gallons as it can lead to overheating injuries. Always check the temperature at the basking spot and in the cool end, with ANY reptile lighting.


UV lighting is quite complex and does take some planning in order to enhance the health of your reptile and keep him healthy. It is best to always do the proper research prior to purchasing your dragon or reptile so you can have the correct bulb in place before ever getting him. It will save a lot of heartache once you have your reptile. Also, Frances Baines' website and lighting charts can help you make a more educated decision on what lighting is the best and which ones you should avoid. That alone will save you a lot of time and money, so, please make sure to read her lighting information. A good rule to follow is that you normally get what you pay for, so if the UVB light is cheap and an unknown brand and not listed on her site or recommended by us, then it may not be very good or even potentially harmful. You do get what you pay for when it comes to UVB lighting.

To view Frances Baines' website please go here:
Special thanks to Frances Baines' contributions for me.

Tracie Kretzschmar, MS