There are four elements to heating and lighting:And just to be clear, why do you not recommend mercury lights? Also, I thought I saw you mention tube lighting - if I use tube lighting, does that mean my tortoise no longer has a "basking area"? Rather a whole enclosure to get UV from? Thanks!!
- Basking bulb. I use 65 watt incandescent floods from the hardware store. Some people will need bigger, or smaller wattage bulbs. Let your thermometer be your guide. I run them on a timer for about 12 hours and adjust the height to get the correct basking temp under them. I also like to use a flat rock of some sort directly under the bulb. You need to check the temp with a thermometer directly under the bulb and get it to around 95-100F (36-37C).
- Ambient heat maintenance. I use ceramic heating elements or radiant heat panels set on thermostats to maintain ambient above 80 degrees day and night for tropical species. You'd only need day heat for a temperate species like Testudo or DT, as long as your house stays above 60F (15-16C) at night.
- Light. I use LEDs for this purpose. Something in the 5000-6500K color range will look the best. Most bulbs at the store are in the 2500K range and they look yellowish. Strip or screw-in bulb types are both fine.
- UV. If you can get your tortoise outside for an hour 2 or 3 times a week, you won't need indoor UV. In the UK, get one of the newer HO type fluorescent tubes. Which type will depend on mounting height. 5.0 bulbs make almost no UV. I like the 12%. You need a meter to check this: https://www.solarmeter.com/model65.html
1. They run too hot for a closed chamber, which is what you should be using.
2. They cause too much carapace desiccation which causes pyramiding.
3. They are fragile and break easily.
4. They are temperamental sometimes and shut themselves off for 20 minutes at a time.
5. They are expensive.
6. Their UV output runs from one extreme to the other. Some produce way too much UV, and other produce none at all after two or three months.