Bearded dragon & blue-tongue skink lighting setup

Housing a bearded dragon and a blue-tongue skink in the same room is totally workable, but you've spotted the real challenge — they do have slightly different lighting and photoperiod needs, and getting both wrong is one of the fastest routes to metabolic bone disease or a chronically stressed animal. Getting heating and UV dialled in is genuinely the single most important thing you can do for both species. To give you the right advice: what enclosure sizes are you running, what bulbs and timers do you currently have for each, and how old is the skink roughly?

Your UV choices are spot on — 12% for the beardie, 6% for the skink, exactly right. The issue is sharing one timer schedule. Adult bearded dragons in the UK do well on 12-14 hour days year-round, but juvenile blue-tongue skinks benefit from slightly shorter photoperiods — around 10-11 hours — to avoid overstimulating their metabolism while they're still growing rapidly. Since they're physically in the same room you can't change the ambient light, but you absolutely can run each viv's lights on independent schedules. The cleanest fix is to put each setup on its own programmable digital timer. I'd recommend the BN-LINK 7-Day Digital Programmable Timer — it's cheap, reliable, lets you set multiple on/off periods per day, and you can stagger the schedules precisely. Get two, one per viv, and set the skink's lights to come on an hour later and go off an hour earlier than the beardie's. That 10-hour window is much better for a juvenile.

It's a fair concern, but in practice it's minimal. The ambient glow from one viv across a room isn't remotely close to the intensity that drives circadian rhythm in reptiles — it's the direct UV and visible light inside their own enclosure that matters. What you do want to avoid is positioning the vivs so the skink's basking end faces the beardie's viv and gets direct spillover heat. Keep them on separate walls or angled away from each other and you're fine. The photoperiod for each animal is controlled by their internal timer, so as long as the skink's own lights are off for 14 hours, a bit of room glow is irrelevant.

Yes, those are both correct. Bearded dragons want 40-42°C on the basking surface, cool end around 25°C — you've got that right. Blue-tongue skinks are a touch cooler, 35-38°C basking, cool end 22-24°C. The key thing with the skink at that age is to make sure you're measuring the surface temperature with an infrared temp gun, not just air temp — juveniles can overheat faster than adults and they'll sit right on the basking tile. If you're not already using a thermostat on the skink's basking bulb I'd add one, but that's a separate conversation. For now, sort the timers and you'll have both animals on independent, species-appropriate schedules without any room rearrangement needed.

Good call — two timers, one problem solved cleanly. Set the beardie to 13 hours for now as we're heading into summer, and the skink to 10. You can nudge both up or down seasonally if you want to be really thorough about it, but even fixed at those settings you'll be well ahead of where you are now. Both animals will be happier for it.