Choosing the right UVB lighting for your bearded dragon is crucial for their health and well-being. Without adequate UVB, they can’t properly absorb calcium, leading to serious issues like Metabolic Bone Disease (MBD). When browsing reptile supply stores, you’ll likely encounter two main types of fluorescent UVB bulbs: T5 High Output (HO) and T8. So, which one is the better choice for your beardie? Let’s break it down.

Understanding UVB and Your Beardie

Bearded dragons in the wild bask under the intense desert sun, soaking up vital UVB radiation. This UVB light converts a precursor vitamin in their skin into vitamin D3, which in turn allows them to absorb calcium from their diet. Without sufficient D3 and calcium, their bones can become soft and deformed, leading to MBD, a painful and potentially fatal condition. Therefore, providing the correct UVB lighting in their enclosure is non-negotiable.

T8 UVB Bulbs: The Traditional Choice

• Lower Output: T8 bulbs have a lower UVB output compared to T5HO bulbs.
• Shorter Penetration: The UVB from T8 bulbs doesn’t travel as far or penetrate as deeply into the enclosure.
• Closer Placement: Due to their lower output, T8 bulbs need to be placed closer to your bearded dragon’s basking spot (typically within 6-8 inches, unobstructed by glass or plastic).
• Common and Affordable: T8 fixtures and bulbs are generally more readily available and often more budget-friendly upfront.
• Suitable for Smaller Enclosures: For smaller juvenile or temporary enclosures, a T8 might suffice, provided it’s positioned correctly.

T5HO UVB Bulbs: The Modern Upgrade

• Higher Output: T5HO bulbs emit a significantly higher amount of UVB radiation.
• Greater Penetration: The stronger UVB output allows for greater penetration, meaning the bulb can be placed further away from the basking spot (typically 12-18 inches above the basking surface, unobstructed).
• Better Coverage: T5HO bulbs often provide a wider spread of beneficial UVB across the enclosure.
• Longer Lifespan (Potentially): While UVB output degrades over time for all bulbs, some keepers report T5HO bulbs maintaining adequate UVB levels for slightly longer periods.
• Recommended for Most Adult Enclosures: Due to their superior output and coverage, T5HO bulbs are generally considered the better option for most adult bearded dragon enclosures (40 gallons or larger).

Which One Should You Choose?

For most bearded dragon owners, a T5HO UVB bulb is the recommended choice, especially for adult dragons in enclosures 40 gallons or larger. The increased UVB output and better penetration provide a more natural and beneficial light source, even when placed at a safer distance.

Here’s a quick guide:

• Small Juvenile Enclosures (Under 40 gallons): A T8 bulb can work, but precise placement within the recommended distance is critical. Monitor UVB output with a Solarmeter 6.5 regularly.
• Adult Enclosures (40 gallons or larger): A T5HO bulb is highly recommended due to its superior output and coverage, allowing for safer and more effective UVB provision.

Important Considerations:

• Fixture Compatibility: Ensure you purchase a fixture specifically designed for the type of bulb you choose (T5HO fixtures are different from T8 fixtures).
• UVB Percentage: Regardless of whether you choose a T5HO or T8, select a bulb with an appropriate UVB percentage for bearded dragons (typically around 10-12%).
• Lifespan and Replacement: UVB output degrades over time. Replace your UVB bulb every 6-12 months, even if it’s still producing visible light. The effective UVB lifespan varies between brands and types.
• Distance is Key: Always adhere to the manufacturer’s recommended distance between the bulb and your dragon’s basking spot. Too close can cause burns, while too far will render the UVB ineffective.
• No Glass or Plastic Obstruction: UVB rays cannot penetrate glass or plastic. The bulb must be placed above an open-top screen lid.
• Provide Shade: Ensure your enclosure has shaded areas where your bearded dragon can escape the UVB and heat if needed.
• Solarmeter: Investing in a Solarmeter 6.5 is the most accurate way to measure the UVB output at your dragon’s basking spot and ensure it’s within the optimal range.

Conclusion

While T8 bulbs can be a budget-friendly option for very small or temporary setups, T5HO UVB bulbs offer significant advantages for the overall health and well-being of your bearded dragon, particularly in standard and larger enclosures. By providing a more potent and better-penetrating source of UVB, you’re ensuring your scaly friend can thrive for years to come. Always prioritize your beardie’s long-term health and invest in proper lighting!