This was mention on another forum recently about 24/7 lights, for the most part most lights even hals are dull compared to day light so is probably more like a sunset/rise to monitors when their up & around.

I don't use 24/7 but it has crossed my mind for creating & ensuring a nest site been created below the surface of deep substrate at 86f??

The centre of this pic is filtered day light through 1 sheet of glass, 2 sheets of 6mm poly & the left is halogen spots flood.