Zoo Med ReptiSun 10.0 High Output UVB Fluorescent Bulb, 17 Watts, 24-Inch Review (2026)

What the 10.0 High Output rating means

Zoo Med rates this bulb as a 10.0 High Output tube, putting out roughly 10 percent UVB and around 30 percent UVA, a stronger dose than the 5.0 line the company also sells for tropical and forest species. That higher output is aimed at desert dwelling reptiles such as bearded dragons and uromastyx, animals that bask under intense, unfiltered sun in the wild and need a correspondingly stronger UVB source indoors to synthesize vitamin D3 and avoid metabolic bone disease. The bulb is a T8 format, meaning it has a 1 inch diameter tube, and it draws 17 watts of power. Zoo Med manufactures the glass in Germany using UVB transmitting quartz, a detail that affects how much of the UVB dose actually reaches the animal rather than being absorbed by lower quality glass.

Coverage, distance, and fixture requirements

At 24 inches long, this tube covers the basking half of a typical mid-size desert enclosure rather than the full length of a larger tank, so a keeper with a longer setup may need to pair it with a second fixture or step up to a longer bulb. Zoo Med states the tube remains effective at distances up to 20 inches from the animal, which gives some flexibility in how high a basking branch or platform can sit below the fixture. Because it is a T8 tube, it only works in a T8 fixture, and Zoo Med explicitly notes that mesh or screen covers can filter out up to half of the UVB the bulb produces, so mounting the fixture directly above open air rather than behind a screen lid makes a real difference in dose.

Lifespan and replacement schedule

Zoo Med states this bulb provides usable UVA and UVB output for up to a full year of typical use, which is the standard replacement window recommended for their fluorescent tubes generally. UVB output declines gradually well before the bulb stops producing visible light, so an animal can appear to be basking under a working light while actually receiving very little UVB from an aging tube. Marking a calendar or setting a reminder at installation is the practical way to avoid running a bulb well past its effective life, since visual inspection alone will not reveal the drop in output. The bulb contains mercury, as fluorescent tubes generally do, and needs to be disposed of according to local regulations rather than thrown in household trash.

How it compares to other UVB options

Zoo Med's own T5 HO ReptiSun 10.0 line, sold in 34 inch and other lengths, produces a notably stronger UVB output than this T8 version, which suits keepers running larger or taller enclosures that need UVB to reach further from the fixture. The 12 inch, 15 watt ReptiSun 10.0 linear lamp is the better fit for a smaller tank where a full 24 inch tube would be oversized for the footprint. Zoo Med's mini compact fluorescent 10.0 bulb trades the linear tube shape for a compact spiral form factor, useful in fixtures that cannot accommodate a long straight tube. None of these alternatives are interchangeable with this T8 bulb without also swapping the fixture, since each format uses a different socket and ballast type.

Bottom line for buyers

Choose this bulb for a mid-size desert or arid enclosure housing bearded dragons, uromastyx, or similar sun-loving lizards, and confirm the fixture is a T8 type before ordering, since the tube will not fit or function in a T5 or compact fixture. Mount it above open mesh rather than a solid screen cover where possible to avoid losing UVB to filtering, and replace it on roughly a yearly schedule regardless of whether the tube still lights up normally. Skip it for forest or nocturnal species that need a gentler UVB gradient, since the 10.0 High Output rating is calibrated for full sun baskers rather than shade dwelling reptiles.

Frequently asked questions