Arcadia T5 90cm 39w UVB Tube

• 850 mm (34") length - built for longer enclosures where a 60 cm tube would leave the far end under-lit.
• Three UV-B strengths - Forest 6%, Desert 12% and Dragon 14%, so the fixture and controller carry over if your UV-B requirement changes.
• T5 HO (high output) - needs a matched T5 HO controller; it will not run on a standard T8 or non-HO T5 ballast.
• 7000K colour temperature (7500K on Dragon) with 30% UV-A, for a daylight-balanced basking area.
• 12 month rated lifespan before UV-B output has declined enough to need replacement.

Arcadia's own open-air readings, Solarmeter 6.5, lamp only - nothing between the meter and the tube. Mesh, glass or acrylic between the lamp and the animal will reduce what actually reaches the basking spot below these numbers.

Against our UV zone bands (Cryptophotic 0-2, Mesophotic 3-5, Euphotic 6-7, Heliophotic 8-10):

• Forest 6% runs Cryptophotic to Mesophotic (UVI 1.2-4.5). Arcadia lists chameleons, day geckos, iguanas, water dragons, map turtles, dwarf crocodiles, rainbow whiptails and blue-tongued skinks.
• Desert 12% runs Cryptophotic to Euphotic (UVI 2.4-6.5). Arcadia lists bearded dragons, uromastyx, tortoises, freshwater turtles and agamids in large enclosures.
• Dragon 14% runs Mesophotic to Euphotic (UVI 3.2-7.0). Arcadia's own guidance is 350-400 mm as the basking distance for species needing a UVI around 6.0, such as adult bearded dragons.

At 850 mm the tube suits enclosures roughly a metre or more in length, where a single 60 cm tube would light the middle third and leave both ends dim. Height clearance requirements are the same as the shorter tube - around 40-50 cm between mounting point and basking perch, more for Desert or Dragon if you want the option of a lower index further from the lamp. In a long, low enclosure, two shorter tubes at each end can sometimes work better than one long tube in the centre - worth thinking through before you buy for an unusually shaped setup.

Tube only. A T5 HO controller/ballast and a reflector are required and sold separately. Fit a guard wherever the animal can reach the fitting.

Suitable for: longer vivariums and enclosures needing even UV-B coverage across their length, matched to species by strength as above.

Not suitable for: short enclosures where an 850 mm tube would extend past the usable basking area; running on a non-HO T5 ballast; nocturnal species with no UV-B requirement.

Do not look directly at an operating UV-B lamp. Position the fitting so the animal cannot make direct contact with the tube - this is a thermal and UV burn risk, particularly for climbing species. Fit a guard where climbing access is possible. UV-B does not pass through ordinary glass or most acrylic, so mount with a clear path to the basking area.

Replace on a 12 month cycle regardless of whether the tube still lights - UV-B output falls well ahead of visible light failing. Keep the tube and reflector free of dust.

• Arcadia T5 60cm 24W UVB Tube - the shorter size, for standard-length enclosures, same three strengths.
• Arcadia T8 90cm 30W UVB Tube - a lower-cost T8 alternative at the same 90 cm length, in Forest 6% and Desert 12%.

Arcadia does not publish a fixed warranty term on UV-B tubes - they are a consumable with an expected 12 month working life, not a defects item. Your rights under the Australian Consumer Law apply regardless. This is a glass fluorescent tube at 850 mm; standard freight applies, packed to avoid breakage in transit.

Is the UV Index at a given distance different on the 90 cm tube compared with the 60 cm tube?

No. UV Index at distance is a property of the strength and the T5 HO family, not the tube length. Length changes how much of your enclosure gets even coverage, not the intensity directly under the tube.

Can I run this on a T5 HO controller built for the 60 cm tube?

No - the controller needs to match the tube length and wattage. An 850 mm 39 W tube needs a controller rated for that length; check your fixture's rated tube length before ordering.

Would two shorter tubes work better than one 90 cm tube?

In a long, low enclosure, sometimes yes - two tubes let you create a stronger zone at each end with a dimmer middle, where one long tube gives more even but flatter coverage. It depends on your layout and is worth planning before buying.

Do I need a reflector with this tube?

Yes, for meaningful output. Without a reflector, UV-B is emitted in all directions and much of it never reaches the animal - Arcadia's distance figures assume a reflector-fitted setup on the T8 lamps and a bare fixture is markedly less effective.

How often does it need replacing?

Every 12 months, on a calendar reminder rather than by eye - the tube keeps lighting well after its UV-B output has dropped below a useful level.