UVB lighting is as essential to most reptiles as food and water. Without adequate UVB exposure, reptiles cannot synthesize vitamin D3, leading to metabolic bone disease, a painful and often fatal condition.

UVB Bulb Types

Compact fluorescent, linear fluorescent, and mercury vapor bulbs each have different characteristics. Linear fluorescent tubes provide the most even UVB distribution. Mercury vapor bulbs combine heat and UVB in one unit. Compact fluorescents have limited coverage area.

Percentage Ratings

Desert species like bearded dragons need high UVB output around 10-12%. Forest species like crested geckos need lower output around 2-5%. Tropical species fall between these ranges. Match the UVB percentage to your species’ natural habitat.

Placement and Distance

UVB effectiveness decreases dramatically with distance. Follow manufacturer guidelines for minimum and maximum distances between the bulb and basking spot. UVB does not penetrate glass or dense mesh effectively; position bulbs above screen tops or inside enclosures.

Replacement Schedule

UVB bulbs lose output long before they burn out visually. Replace fluorescent UVB bulbs every 6 months and mercury vapor bulbs every 12 months, regardless of whether they still produce visible light. A UV meter verifies actual output if you want precision.

Photoperiod

Provide UVB lighting on a consistent 10 to 14 hour cycle that mimics natural daylight. Use timers for consistency. Some species benefit from seasonal photoperiod adjustments that simulate longer summer days and shorter winter days.

Common Mistakes

Placing UVB on the wrong side of glass, which blocks UV transmission, using the wrong percentage for your species, mounting bulbs too far from basking spots, and failing to replace expired bulbs are the most common UVB-related errors that lead to health problems.