Can a full spectrum light be substituted for a UV light?

I’m not certain, but I don’t think so. If you have a window that gets a lot of sunlight you can try leaving him (her) there while the sun is shining. Pet stores usually have UV lights that can clip onto things, too.

No. Turtles need the UVA for production of Vitamin D just like people. Unfortunately, window glass is cleverly designed to cut out the UV your turtle needs.
You can purchase the correct light from your neighborhood pet store.

Here is a link that discusses UV for turtles.
Enjoy your turtle.

yea, you def need a UVA bulb. I believe you need UVB as well but not positive in that regard. They need the light for calcium production in their shells, without it, their shells will start to rot and theyre likely to get a disease. Ive seen it happen before and its not pretty.