5.0 Or 10.0 UVB for turtles – Which of these is the best?

Ultraviolet lighting is important for turtles as it helps them in completing various physiological functions such as calcium metabolism and Vitamin D3 production. A lack of proper UV light could cause your turtle to develop adverse health conditions such as deformed bones.

Turtles in the wild are able to get sunshine to their fill, and even when their environments get cold, they migrate into warmer tropical regions to continue enjoying the sun’s rays. These emissions from the sun provide essential ultraviolet rays that aid in the growth and development of not just turtles, but almost all living organisms on earth. Turtles require ultraviolet light for different purposes, the most important being calcium synthesis and absorption as well as Vitamin D3 production in their bodies. They also need the sun to bask in and dry their shells.

Many turtles that are kept as pets unfortunately go without this essential natural commodity. The problem is observed in places where the pet owners are unaware that these reptiles need the sun, and also in places that do not enjoy lengthy periods of natural sunlight. Artificial sources of these rays have since been developed, and are used in turtle tanks and enclosures to ensure your pet gets the much needed exposure to ultraviolet light.

What does your pet turtle require from the UV Rays?

It is important to note that there are different ultraviolet rays, and they have varying wavelengths. This variation is what differentiates them. There are UV-A, UV-B and UV-C rays. UV-A rays are important for turtles as it facilitates their bodily metabolisms and sets the mood for their breeding. UV-B rays are important in the manufacture of vitamin D3 for proper bone formation and prevent the turtle shells from deterioration which may cause your turtle to die.

The UV-B rays are also present in two different intensities which are the 5.0 and 10.0 UV-B rays respectively.

What are the differences between the 5.0 UV-B and the 10.0 UV-B?

Ray intensity

These two rays vary in the intensity of ultraviolet emissions they put out. The 5.0 UV-B lights give off 5% ultraviolet intensity and have a lower penetration power.

The 10.0 UV-B bulbs emit 10% intensity and are likely to penetrate a turtle’s shell faster.


While both of these lights are built for turtle enclosures, their varying intensities make them suited for different environments. The 5.0 bulbs are better suited for small enclosures with a low turtle population.

For a larger enclosure with more turtles, the 10.0 is the best option as it has a higher penetration power and will cover a bigger area.


Owing to their different penetration power and ultraviolet intensity, the bulbs are mounted at different distances from the turtles. The 5.0 bulbs, which are meant for smaller enclosures, are mounted at a distance of 8” away from the turtles.

The 10.0 UV-B bulb is mounted at a distance of 10-12” from the reptiles.

The below table will offer a summary of the main differences between the 5.0 UV-B and 10.0 UV-B bulbs.

5.0 UV-B
10.0 UV-B
Ray Intensity
5% ultraviolet light
10% ultraviolet light
Small enclosures with small turtles and low population
Larger enclosures with bigger turtles and higher population
Should be placed approximately 8 inches away from turtles
Should be placed at a 10-12 inch distance from the turtles

Having seen the main differences, let us review two major UV-B bulbs for turtles.


Zoo Med Aquatic UV-B Kit


This kit combines a light bulb of 13 watts and a heating lamp that has a power of 50 watts. This innovative kit is ideal for beginners with a small enclosure, and serves its purpose diligently. It is convenient for you since you do not have to buy two separate lamps for light and heat.


  • Combines both heat and light emission
  • Sturdy construction that integrates polished aluminium for more light and heat reflection
  • The bulb is safely tucked away from reach, ensuring longevity.


  • It is small in size, and cannot be used for large spaces.


View price on Amazon




This bulb is better suited for desert turtles as it mimics their natural habitat for optimal response and growth. The 10.0 UV-B outputs allows for turtles to bask and produce sufficient amounts of vitamin D. this Bulb will comfortably last you one year, which is quite a bargain considering the intensity of output. In case of a small enclosure, a screen can be used to filter off excess UV and regulate penetration to the desired intensity.


  • It can be used for larger enclosures with many turtles.
  • It is good for desert turtles as it creates an environment similar to the desert.
  • It lasts at least a year, which is a good length of time.


  • This light needs to be mounted on a metallic dome that is then attached to the tank.


View price on Amazon



The choice between 5.0 and 10.0 UV-B bulbs is dependent on several factors such as the size of the enclosure and types of turtles you have as pets. I would recommend the 10.0 UV-B lighting since you would not have to change it in case you intend to expand the enclosure. You can also use a screen to regulate the UV intensity.


Where can I purchase these lights?

Sites such as Amazon are a reliable source of genuine bulbs and other equipment that you may need for your pets. Exotic pet websites also sell merchandise for the same.

Do I need to keep the lights on throughout?

No, the UV-B lamps only need to be on for 8-12 hours. This is enough time for your reptiles to absorb the UV they need.

Must I buy a separate bulb for heat?

This is determined by the choice of bulb you purchase. Some bulbs combine heat and light, others come separately.

Kerry Blake

Since I was young, I have always had a thing for sea creatures. Being raised along the beach gave me the chance to interact with all kinds of reptiles, including turtles. I have always found this creature quite fascinating, and at a young age, I asked my parents to get me one as a pet. My love for turtles is what inspired me to pursue marine science when I got to college. Specializing in this field made learning so much about such reptiles. If you would like to get a pet turtle at your home, this guide will be of great help.

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