I kinda lean with Doc. We have a light that we use at night when we are NOT in the pool. But we don't have teenagers to " keep an eye on". Our light is a 12/15 volt as Carl suggests that is accessible from inside the pool. I replaced the housing once (not the niche) without difficulty. Make sure to have a connection between the 12/15 volt transformer wire and the light wire in an accessible spot.

Actually, we did use the light while in the pool when my daughter and grand daughter visited in November. The water was only 74 degrees, but she wanted to go in, so in I went