Zoo Med ReptiSun T5 HO Reviews + Verdict for Bearded Dragons

The short version

What's good:

• One of only two or three brands keepers trust to deliver the UV index a bearded dragon needs.
• A T5 HO tube holds usable output about twice as long as the older T8, so you replace it yearly instead of every six months.
• Cheap for what it does, and easy to find.
• Fits Arcadia fixtures, so you're not locked into one brand's hardware.

What's not:

• You can't verify the output without a UV meter that costs several times the bulb.
• Owners report fit problems. One keeper got two replacement tubes running 1-2mm too long for the fixture.
• A live community dispute over Poland-manufactured tubes, unmeasured on both sides.
• The bare bulb is half a purchase. You still need a T5 HO fixture with a reflector.

Which reptiles and setups it fits

Buy it for:

• Bearded dragons and other desert species, in the 10.0 grade this bulb was built around.
• Enclosures where a tube can span roughly two thirds of the length.
• Keepers who already own a T5 HO fixture, Arcadia included.

Pick something else if:

• You keep forest species and need the lower 5.0 grade.
• You want one box that solves everything, in which case a fixture kit saves you a second purchase.
• Your basking zone sits more than about two feet from the tube. That's where keepers move to Arcadia's higher percentages.

The specs that matter

Grade, length, tube standard. Brand comes after those.

• Grade: 10.0 is the desert-species output, 5.0 is the forest one. Not a more-is-better scale. Match it to the animal.
• Length: the tube should span about two thirds of the enclosure so the animal can't spend its day on an unlit side. Buy the length that fits the tank, not the one that's cheapest.
• T5 HO, not T8: different effective distances, different fixtures, different replacement intervals. A T5 tube won't drop into a T8 fixture and behave.

Wattage follows from the length you picked.

How it keeps your animal safe

A bearded dragon without UVB can't process calcium properly, and that road ends in metabolic bone disease. So what you need from a bulb is that it puts out the UV index the animal needs, at the distance you've mounted it, for as long as you keep it in the fixture. The hobby's answer is that only a handful of brands have been tested enough to trust on that. This is one of them. The keeper shorthand is blunt: ReptiSun T5 HO 10.0 or Arcadia 12%, and treat the rest as too weak to bother with.

You can't confirm any of it by looking, though. Output decays invisibly. The colour of the light tells you nothing about the UV coming off it, and the cheap UVB test cards sold alongside these bulbs aren't reliable for reading output. A Solarmeter is the only real instrument, and it costs several times what the bulb does, which is why most keepers don't own one and run on brand reputation plus a replacement schedule instead. That's a reasonable way to live. It's also trust rather than verification, and we're not going to pretend otherwise.

Two things you control matter as much as the bulb: distance and mesh. A screen top absorbs a meaningful share of the UVB before it ever reaches the animal, and effective distance differs between tube standards. Keepers target a UV index in the low-to-mid 4s at the basking spot. You get there with grade, distance, and whatever sits in between.

Build quality and living with it

It's a fluorescent tube. Build quality means: does it arrive intact, does it fit, does it hold output as long as the box claims.

The fit complaint is concrete. One keeper ordered the same ReptiSun model they'd been running, found the tube 1-2mm too long for their fixture, and the vendor's replacement had the same problem. Two in a row points at a batch rather than a bad single unit. Small margin to lose a purchase over, and it's the clearest knock on the hardware.

Lifespan is where the T5 HO format earns its keep. Older T8 tubes want replacing about every six months; a T5 runs roughly twelve, and Zoo Med's box says a year. Plenty of keepers swap at six to eight months anyway, whatever the brand, on the logic that a bulb is cheap and a calcium deficiency isn't. Without a meter, there's no arguing them out of it. Budget one tube a year. Two if you'd rather not think about it.

Then there's the Poland argument. Keepers are reporting a visible change in hue on tubes made there and worrying aloud about the phosphor mix. It's worth reporting and it isn't worth a verdict, because nobody on either side has measured anything. The people raising the alarm are describing the colour of the light; the people pushing back note that hue tells you nothing about UV index and that the keeper who raised it owns no meter. That's where it sits. If it turns out to be real, this score moves. For now it's an unresolved concern, not a defect, and you can weigh it yourself.

How it compares

• Versus Arcadia T5: the other half of the duopoly, and what keepers reach for when the basking zone sits far from the tube, where Arcadia's higher percentages have the headroom. Arcadia usually sells as a complete fixture kit, several times the price of a bare ReptiSun tube, but it arrives ready to hang. The two are cross-compatible: a ReptiSun tube drops into an Arcadia fixture.
• Versus compact and coil UVB: not a real comparison. Serious keepers run linear tubes, and a coil bulb lights a fraction of the enclosure. The ReptiSun name appears on compact bulbs too, and those aren't what this review covers.
• Versus T8: the older standard. Weaker, shorter effective distance, replaced twice as often. Buying new, buy T5 HO.
• Versus Exo Terra T5: the newest name on the trusted list. At least one long-term keeper rates Exo Terra above Zoo Med on both output and product life. A minority report, but it comes from someone with years on both.

Setting it up

Mount the tube so it spans about two thirds of the enclosure, over the basking end. Measure from tube to basking surface, and account for the screen top in between, because the mesh takes a cut. Aim for a UV index in the low-to-mid 4s where the animal sits.

Write the install date on the tube in marker. That one habit removes most of the anxiety about decay, because the failure mode here isn't dramatic. It's a bulb going quietly flat a year in while everything still looks fine. If you'd rather know than assume, the Solarmeter 6.5R is the instrument, at many times the price of the bulb. Most keepers skip it and replace on schedule.

Our call

Buy it. In a category full of bulbs that don't do the job, this is one of the two that does, it's the cheaper of the two, and it drops into the other one's hardware if you change your mind later.

Go in clear-eyed, though. You're buying a trusted tube you can't personally verify, from a brand currently arguing with itself about a manufacturing change, and you'll replace it on a calendar rather than on evidence unless you spend more on a meter than you would on years of bulbs. That's UVB, not this bulb.