Iguana lighting in a basement flat

A basement flat with no natural light is actually one of the most demanding environments for a green iguana — these animals evolved in open tropical canopy and need intense, high-quality UVB to synthesise vitamin D3 and process calcium. Without it, metabolic bone disease sets in faster than most owners expect. Getting heating and UV lighting right is genuinely the single most important factor in iguana health — more than diet, more than enclosure size. To give you the right recommendation, tell me: how old is your iguana and roughly how big, what size is the enclosure, and what lighting or heating do you currently have running?

That cheap UV strip is almost certainly the main problem. Budget starter-kit UVB tubes degrade rapidly — often within three to four months — and many never produce meaningful UVB output to begin with. For a 4-foot adult iguana in a basement with zero ambient natural light, you need a genuinely high-output T5 HO tube at 12% UVB, and it needs to run the full length of the basking zone. What's the length of the basking area in the vivarium, and is the UV fitting currently mounted inside the enclosure or sitting on top of a mesh lid?

Mesh cuts UVB transmission by around 30–50%, so your iguana is getting a fraction of whatever weak output that tube produces. That setup needs a complete overhaul. My clear recommendation is the Arcadia T5 HO Reptile Lamp 12% UVB in the 54W/46-inch size, paired with an Arcadia T5 Slimline Controller Canopy — mount it inside the enclosure, directly above the basking branch, no mesh in between. Arcadia's 12% tube is specifically rated for large iguanas and high-canopy species; it produces meaningful UVB at distances up to 50–60cm, which matters given how tall your vivarium is. The controller canopy is reflector-fitted so none of that output is wasted upward. Replace the tube every 12 months even if it still looks bright — UVB output drops well before the visible light does. For basking heat, keep your halogens but aim for a surface temperature of 48–52°C directly on the basking spot.

With a correctly installed Arcadia 12% T5 HO tube running 10–12 hours daily, a healthy adult iguana should synthesise enough D3 through her skin — that's always preferable to supplementation because the body self-regulates it. That said, given she's been on inadequate UV for an unknown period, I'd add a light dusting of Repashy Calcium Plus LoD (low vitamin D) twice a week for the first three months while she recovers. Avoid high-D3 supplements long-term alongside proper UVB — oversupplementation causes its own toxicity problems. Once the new lighting is established and she's looking well, drop to occasional supplementation or none at all.

Yes, and it's worth getting right. Put the T5 and basking lights on a timer — 13 hours on in summer (roughly May to August) and 11 hours on in winter. Green iguanas are equatorial but they do respond to modest seasonal variation, and a consistent artificial photoperiod prevents the hormonal disruption that comes from random or constant lighting. A simple plug-in mechanical timer does the job perfectly. The key point is consistency — same on and off time every day, no interruptions from room lights during the off period if you can manage it.