Redearslider.com :: Lighting Issues

There should be no barrier between any UVB source and your turtle. Glass and plastic are treated to block the passage of any significant amount of UVB rays. For safety measures, and to prevent adventurous turtles from climbing out, a screen is highly recommended. The screen should have at least a grid spacing of 1/2”. Do not rest lamps on top of glass since that will cause a serious fire and electrical hazard.

Electrical Timer

Depending on the manufacturer and strength, fluorescent UVB lights should be positioned about 10-12” away from the basking area, while UVB heat lamps should be about 18-24” away. These are rough estimates and you should carefully follow the manufacturer’s instructions. They should be positioned and directed over the basking area, which is where your turtle would be out of the water and able to fully absorb these rays.

It is recommended that you mimic your turtle’s lighting with your area’s season. Therefore, the lights should be on longer during the summer than the winter. A simple electrical outlet timer will make it easier for you to maintain a photoperiod and thermoregulation in your turtle’s environment.

Purchasing UV Lights

Despite some complicated information, it is relatively simple to provide the necessary lighting and basking conditions your turtle needs. There are a number of different ways and here is a quick look at some recommended combinations you can use for an indoor setup:

A UVA/UVB fluorescent bulb and an incandescent light bulb for heat. Incandescent light bulbs are standard household lights and you need to make sure your RES cannot splash water on it or come into contact with it. You can also consider halogen lights and red heat bulbs.
A UVA/UVB fluorescent bulb and a ceramic heat-emitting bulb. Ceramic heat-emitting bulbs that provide no light. They are also heavier, so a well-supported lamp is required. It has come to our attention that fluorescent lights should not be the only source of light your turtle receives.
A mercury vapor bulb providing UVA, UVB and heat. These bulbs produce a lot of heat and are larger and heavier than standard bulbs. A well-supported lamp is required and make sure your RES cannot splash water on it or come into contact with it. They need to be kept further away and are more expensive than fluorescents but provide more UVB and have a longer lifespan.

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.

Measuring UVB Output

Content coming soon.

Further Reading

There are plenty of other sources of information regarding UV light and basking for turtles and other reptiles. Here are some recommended sites:

Analysis
Understanding Reptile Lighting Systems http://tortoisetrust.org/articles/lighting.html
Lighting and heating for Reptiles http://www.anapsid.org/liteheat.html
UV-lamps for Terrariums http://www.testudo.cc
ATP Turtle Care: Lighting http://www.austinsturtlepage.com/Care/care.htm#Lighting

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

Reference
UVB Output of Various Bulbs http://carolinapetsupply.com/uvb_output_of_bulbs.htm
Reptile Lighting http://www.anapsid.org/uvtable.html