I am often asked what bulb I recommend for various pet reptiles, especially for those that require both heat and full spectrum UVB lighting. There are several options for providing the needed heat for your diurnal (daytime) pet reptile, as well as the UVB needed for proper vitamin D3 and calcium absorption. My personal favorite method for providing heat, visible light, and UVB wavelengths of light is to use a mercury vapor bulb – in particular, the ZooMed Powersun Bulb.
The Powersun emits substantial amounts of both UVB and heat, making it ideal for desert dwelling reptiles or for species that prefer to bask at high temperatures. It also allows yourreptiles to behave in a more natural fashion; the bright, white light that is making them warm is also what is emitting all the UV, similar to sunlight. Artificial lighting is nowhere close to the range of light that the sun emits, but by providing intense heat and UVB in one place, you do allow your pet to seek out the conditions it would in the wild. To metabolize D3 in the wild,reptiles need to be a certain temperature, while also receiving exposure to UVB. This is true for most animals, including humans. “Most vertebrates can either absorb vitamin D from the diet or synthesize it in the skin from 7-dehydrocholesterol using energy from ultraviolet (UV) light of certain wavelengths (290–315 nm) in a temperature-dependent reaction.” (merckmanuals.com) The importance of properly heating your reptile, in addition to providing adequate UVB and supplementation, suddenly becomes much clearer!
For your pet reptile to properly utilize vitamin D3, then, it needs to be warm enough while it is digesting its meal and absorbing that all-important calcium (as well as other vital nutrients). The reason the PowerSun is one of my favorite bulbs of all time becomes clear when you realize that in order to bask, your bearded dragon, blue tongue, lacerta, or other basking pet is not only getting the temperatures it needs under the light, but UVB as well, all at the time when it is actively seeking it out.
Blue Tongue Skink basking under a 100 watt Powersun Bulb
PowerSun bulbs come with a year-long warranty from ZooMed, and when used correctly, have a lifespan much longer than that. I would suggest switching out your bulbs for optimal UVB output every 10 to 12 months. I prefer to use a UVB meter to check UVB output on older bulbs, and often use older bulbs on cages where UVB is less important or where lower amounts of UVB are even preferred (my Frilled Dragons, for example, did much better under older bulbs that emitted lower amounts of UVB than new bulbs did).
To get the longest life from your bulb, make sure to read and follow the instructions that come with it. These bulbs do best mounted vertically, straight up and down, and will last the longest if they are not jostled or moved frequently. They are self-ballasted, and can be screwed into any regular light fixture. However, it highly recommended to use a deep dome or 10” dome light fixture to allow for proper air flow around the bulb, both to prevent overheating and to keep the bulb from protruding out of the bottom of the fixture. As a safety feature, these bulbs turn off automatically when they reach a certain temperature, or when heavily jostled or knocked over. Once turned off, they require a cool down period before they can turn on again, so if your bulb does not immediately turn back on, give it 5 to 10 minutes and then try again.
We use PowerSun bulbs in our stores on our chameleon cages
Lastly, these bulbs are big, hot lightbulbs. I only recommend them for larger enclosures; the smallest being an 18” x 18” x 24” front opening terrarium, or a 36” x 12” x 12” (or similar footprint) glass cage. Keep in mind that in shorter enclosures, your pet cannot bask further away from the light if it wants, and in shorter cages the PowerSun may not always be the most suitable bulb. Like all bulbs that produce heat, the PowerSun does naturally dry out enclosures it is used on, so for young animals or tropical species, extra attention should be paid to the humidity within the enclosure. It is alright if it dry directly under the light if the rest of the enclosure is able to maintain humidity, or if a humid hide is provided.
Nutrition in Reptiles, retrieved July 20th, 2013 from http://www.merckmanuals.com/vet/management_and_nutrition/nutrition_exotic_and_zoo_animals/nutrition_in_reptiles.html