Well, at USC there's a pool within a block of the greek village at the gym (outdoor and indoor) so I think it's safe to say that our girls would probably rather a tanning bed. Though, ZTA has a sister that has a spray tan salon and she'll bring the stuff to them every once in a while, so I guess that's practically like having a tanning bed in the house.
And if you don't want to get rid of the library, you could always convert one of the bedrooms.