She has a double-dome lighting fixture with a 75 watt Repti-Tuff heat bulb and a 13 watt UVB bulb which sits about 11" above the floor of her basking area. Three weeks ago I replaced the old, crappy turtle ramp (the kind that affixes to the tank with suction cups) with a gorgeous redwood and Plexiglas "house." The basking area is 18" x 18" and has a large hole at the top for the lamp (her previous set-up was using a 90 watt heat bulb that was about 13-14" from the bottom of her basking area before). The reason I made the change was to give her more swimming room. I was able to add roughly 12-15 gallons of water to her tank, which is kept pretty darn clean if I do say so myself. Anyway, she will not bask. She will not go up to her basking area. It is roughly 85-95 degrees inside, depending upon where I point the laser temperature reader thingy (not quite as warm as her previous basking area, which was at 100+ in places). She will however, go up there if I lure her with salmon. So she CAN go up there--she just chooses not to. I read here that turtles can be persnickety about change but it's going on three weeks and I'm concerned that she is not getting the UVB lighting she needs.
Proper Lighting for your Turtle Habitat - My Turtle Cam
Another kind of light that many people like to use is called a , or simply a "night light." These usually come in either red or purplish-blue and are designed to allow night viewing without keeping your turtles awake all night and making them grouchy. They can also provide some heat, which can be important for hatchling turtles, who often sleep on the basking area at night. Adult turtles don't need night lights, and most turtles don't care whether they're red or blue as long as they're not too bright. I've noticed that a few turtles seem to be kept awake by red light, but not by blue, so I usually choose blue.
What's The Best Turtle Basking Light Wattage? | TurtleHolic
Another kind of night viewing lamp called an . They're designed to produce heat as well as (usually) red light. Some provide mainly heat and little or no light. Their purpose is to keep your turtle's basking area warm, which is mainly important for hatchlings, who often sleep on the basking area because their lungs are still very small. Once they get a little bigger and can hold their breath for a long enough time, they start sleeping underwater.
I have two deep dome lights over my 75 gallon tank