Redearslider.com :: UVB Lighting Sources

Keeping turtles indoors means that we need to artificially provide UV sources for them. (Refer to the previous section, Lighting Overview, for their importance.) In addition to occasionally offering sunlight, there are various types of bulbs that can be used for these purposes. This section is an examination of those special UVB sources. However, not all of these produce enough heat for basking. Those that do are noted; and for more basking heat sources, please refer to the Basking Overview section.

While most common light sources offer a usable amount of UVA, by design they filter or do not emit UVB. Since UVB is a necessary element for Red Ear Sliders, special bulbs are required to provide them. UVB rays are not in the visible light spectrum and UVB bulbs will continue to emit light after they have stopped emitting UVB.

Sunlight (UVA, UVB, Heat)

There is no substitute for direct, unfiltered sunlight. Taking your turtle to enjoy some sunlight on a warm, sunny day is highly favorable. With about 5 hours of sunlight over the course of a week, it may not be necessary to have a dedicated UVB bulb. However, having proper lighting and basking conditions inside is still recommended. At anytime during the day, your turtle may want to dry off and bask and should not be prevented from doing so.

Temporary outdoor enclosures and pools can be used to allow your turtle to get some beneficial sunlight. Be advised of the hazards of keeping turtles outside unattended and make sure shade is available to avoid hyperthermia. Putting a tank in direct sunlight will also cause a fast and deadly spike in temperature as well as block the intended UVB rays. If you choose to keep your turtle indoors and outdoors, make sure you have read the Outdoor Enclosures section.

Fluorescent Bulbs (UVA, UVB)

For indoor setups, most turtle keepers provide UVA and UVB through special fluorescent bulbs. These bulbs are specially manufactured to emit UVB rays and have special glass casings that allow the rays to pass through. They come in different sizes and strengths but produce very little heat since they are low-wattage. It is beneficial to have a bulb that produces approximately 5-10% UVB. These bulbs are generally effective for about 6-10 months and will need replacement afterwards. Fluorescent UVB bulbs do not project UVB very far, so it is necessary to have it positioned closely - 10 inches above the basking area would suffice.

Aquarium hoods, which should have any glass or plastic barrier removed, can hold tube shaped fluorescents. Certain specialized hoods can hold the compact versions as well as basking lights. Compact fluorescents, which resemble energy efficient bulbs, utilize standard sockets and can fit into most light fixtures. These bulbs have a ceramic base, are longer and heavier than an equivalent incandescent light bulb. Extra care needs to be taken to make sure they are installed correctly.

Comment: Avoid cheaply made brands and make sure a fluorescent UVB’s packaging states UVB output between 5-10%. Purchase these bulbs from reputable dealers and stores and avoid online auctions. Fluorescent UVB bulbs still provide light after they stop providing UVB. They have a limited life span and need regular replacement.

Full Spectrum Bulbs (UVA, UVB?)

Light from the Sun is full spectrum and covers the entire spectrum from low ultraviolet to visible light to infrared and above. There are several different brands of lights described as “full spectrum” or “natural daylight” bulbs and you should avoid them all. While some of the bulbs are advertised as “full spectrum”, others mention it in the product packaging. Most of these bulbs may not produce any significant (or any) amount of UVA, UVB or heat. Full spectrum bulbs are usually in the form of fluorescent varieties. Any fluorescent bulb you purchase should state that the product produces UVB of about 5-10% on its packaging.

Mercury Vapor Bulbs, UVB Heat Lamps (UVA, UVB, Heat)

An increasingly popular choice for large enclosures is a self-ballasted mercury vapor bulb (MVB); also known as a UVB heat lamp. It is the only bulb, which resemble normal floodlights and spotlights that can produce UVA, UVB and heat. Though they can be used in most standard sockets, those sockets must be able to withstand the wattage and heat generated. Lamp fixtures must state they can accept these higher wattages. They normally have sockets that are made of ceramic or porcelain.

MVB

Though they work very well, they are more expensive than other UVB lights. However, these bulbs provide light, heat and significant amounts of UVA and UVB rays – more than any available fluorescent bulb can. They last longer than those fluorescent counterparts and eliminate the need for a secondary lamp for heat. Since the strength of the output is considerable, the bulbs should be positioned further away than a fluorescent UVB fixture. Carefully follow the manufacturers' special instructions and do not look at these bulbs directly.

MVB Commentary
Reptile Lighting: A Current Perspective http://www.anapsid.org/gehrman2.html
Mercury Vapor Heat & UV Lamps http://www.anapsid.org/mercuryvapor.html

Specialty Lights

Often turtle supplies are grouped with reptile supplies that for the most part are justifiable. However, specialty lights are one area you should avoid altogether. For example, black lights produce large amounts of UVA and can be harmful. Other lights offering nighttime viewing should also be avoided since they may disturb your turtle. Your RES might not benefit from these lights and it might even cause harm to their vision.