The Proper Lighting of Aquatic Turtle Enclosures
(Part 2 of the Turtle-Tech Heating & Lighting Series)
As we mentioned in Part 1 of this series, articles on Heating and Lighting reptile enclosures are usually lumped together into one blanket article. Although these two issues have plenty of overlap, we find it helpful to separate both and address them separately. This gives the adequate time and space needed to truly provide some helpful, useful knowledge. Part 1 of this series deals with the specific heating concerns generally associated with turtle habitats. While in this- Part 2, we deal more specifically with the Lighting aspect of the turtle enclosure. Full spectrum ambient light, including both UVA and UVB aspects, along with supplemental directional lighting will all be addressed in detail so that you may have the appropriate information available to make educated decisions on properly lighting your turtles home. The importance of providing proper light (and Heat) sources for reptiles cannot be overstated. Being cold blooded creatures, reptiles depend on environmental heat and lighting for virtually all life giving functions. Without these two elements in proper quantity and form, the long term likelihood of success with your turtles is slim.
So below, the Turtle-tech team takes you through what you need to know about understanding the basic principles of properly lighting your turtles environment. Hopefully without too much “technical overload”.
First, as cold blooded reptiles, Turtles depend on the light and heat from the sun for powering basically all of their life functions. Plainly said, reptiles cannot survive extended periods of time (outside of winter dormancy) without the suns interaction. When these reptiles are removed from the wild state where they have free access to this interaction with the sun, and placed in captivity away from that direct access, it becomes the responsibility of the keeper to provide a proper “replacement” for the sun. Fortunately for us, because of modern advancements in lighting technology we are able to duplicate the sun’s rays and heat well enough to provide for our turtles health and wellbeing.
The Basics of lighting:
Sunlight consists of several spectrums of light (colors). There are the normal visible light waves between 400-700 nanometers (nm) -these are the colors we see as the rainbow. The UV light spectrum (100-400 nm) which includes UVA, UVB, and UVC wave-lengths, and infrared heatwaves above the 700 nm range.
The most important area of concern for pet turtles (and most reptiles) is the 280-400 nm section of the UV light spectrum, this is where both the UVA and the UVB wavelengths are produced. Many of these particular light spectrums are not normally produced by average home lighting products, so must be added specifically into our turtles captive environment by specially designed lighting selections.
Why is UVA and UVB light so important to our turtles? Let’s take a look:
UVA light: Visible light that we see every day, and the UVA light we cannot see, are both extremely important to reptiles. Because of the evolution of the reptilian eye that recognizes the UVA light spectrum, turtles see more colors then we do. The presence of UVA light-waves allow the turtles to use these extra colors in the course of everyday actions such as recognizing different food sources or determining the length of the day/night photoperiods (circadian cycle). Most commonly used halogen basking lamps produce some UVA along with the normal visible light (and of course heat), but most UVA light is produced by fluorescent tubed lighting specifically designed for this purpose. High intensity discharge lighting such as Metal Halide or Mercury Vapor lighting are also good producers of UVA.
UVB light: The UVB light wave is the part of the light spectrum that allows reptiles to synthesize and store Vitamin D3, which is vital in assimilating calcium into the body. UVB also is involved in the manufacture of hormones responsible for controlling blood calcium levels and bone densities. UVB light is not produced by normal household lightbulbs and must be specially provided for by fluorescent tubed lighting specifically designed for this purpose. Newly designed High intensity discharge lighting such as Metal Halide or Mercury Vapor lighting are also good producers of UVB. UVB is not produced by LED lighting.
So now we understand the importance of these forms of lighting to our turtles health and wellbeing, without this proper full spectrum “sunlight”, turtles can have difficulty feeding, having correct sleep periods, generating vitamin D3, and run the risk of calcium deficiencies and even metabolic bone disease. In the turtles captive environment, it is up to us to provide this “replacement” for the sun. But how do we deliver all these special forms of light? thankfully it’s a lot easier than you might think.
Providing the Sun:
There are two ways to make sure your turtles have the correct UVA and UVB light waves needed to remain healthy. The first way is to provide your turtles time out in the natural sunlight for a few hours three or four times a week. This should be adequate exposure to the sun’s rays to prevent any UVA or UVB deficiencies. But this requires a lot of effort and moving around of the turtles, so if you can’t see yourself having the time or access to provide consistent outside basking time in the natural sunlight year round, a supplemental UVA-UVB lighting unit on your turtles aquarium is the answer.
Fortunately, there are a few good reptile product manufacturer’s that offer lighting units and the specialized lamps that produce UVA and UVB light spectrums – Zoo Med and Exo-Terra are two good examples. These lighting units can easily be purchased in both compact versions and full tank length versions, in a variety of shapes, styles, and price ranges. Each aquatic turtle setup is slightly different: tank size and dimensions, the amount of dry space versus water space, the type and location of the basking area, and even the cover of your aquarium will all determine the type, size, and positioning of your new UV lighting unit. Units vary by brand, so it is best to research your choices based on the manufacturers recommendations for your size aquarium, however we can offer a little general help and guidance to get you started.
First, it is generally excepted that the long tube versions of the UVA-UVB fluorescent bulbs are preferable (over the compact versions). These bulbs disperse the lighting more evenly throughout the enclosure and last longer before needing to be replaced. However in some applications the compact versions certainly have their place. These bulbs are usually offered in different wattages and intensities, a 5.0 or 10.0 UVB output for example. The manufacturer will recommend the size to use and its placement above the aquarium based on your tank size and height. For most aquatic turtles, which are true basking reptiles, the more intense UVB (for full mid-day basking species) is usually suggested, the proper spacing of the unit above the aquarium will allow the correct UVB intensity at the turtles basking spot, commonly this is around 12 inches above the turtles carapace when basking, but again just follow the manufacturers direction with the unit you chose. With the proper sized UV light, suspended at the suggested distance from the basking area, you’ll be able to provide the correct UVA and UVB light required. Remember, UV rays do not penetrate through glass, so a glass aquarium top cannot be used. Also, it is suggested that terrestrial turtles (box turtles/tortoises) have a shaded area where they can escape the UV light if they need, this will allow them the opportunity to self-regulate the amount of UV light they are exposed to. Aquatic Turtles can self-regulate the amount of UV light they receive by spending time in the water, as water (like glass) blocks most UV waves.
Basking Lights:
Common basking lights are also a basic requirement for providing good normal visible light within the enclosure. Where they produce some small amounts of UVA, they are mostly utilized for their heating aspect, they produce no UVB. These basking lamps, in conjunction with the supplemental UVA-UVB lighting unit combine to cover all the basic lighting requirements and even some of the heating necessities (a complete overview of basking heat lamps are covered in Part 1 of this series).
And finally-Combination HID Lighting:
There is one other method of lighting that is generally restricted to larger
turtle enclosures, this is the use of HID bulbs or “high intensity discharge” units. These use high output Metal Halide or Mercury Vapor lamps that not only produce ample amounts of visible light (along with UVA-UVB) but also produce heat, combining the primary full spectrum lighting and the heat source into one (at least during daylight periods where the lamps are in use). New developments with these type lamps have produced smaller, more user-friendly versions suitable for more moderate sized enclosures and have improved the UVB output and consistency from the original HID bulbs. In the proper sized environment, with supplemental nighttime heating, these HID lighting units can be an option worth considering.
So there we have it. As mentioned above, the importance of providing proper lighting and heat sources for our turtles cannot be overstated. We hope that this insight into the Proper Lighting for Aquatic Turtle Enclosures, and its sister article “The Proper Heating of Aquatic Turtle Enclosures” has help address some of the questions regarding these two topics and offered some helpful answers.
