Monday-Friday it is open from 6am to 9 or 10 pm. On Saturdays it opens at 7am. I'm not sure when it closes.Sundays it is closed. The day rate when I was there recently was 125 pesos and I think the weekly rate was 400 pesos or thereabouts. It has all the free weights you could want and many machines that are not too modern but get the job done.
Upstairs they have bikes. A couple of treadmills and Elipticals. There is a locker room and a place to shower. You're looking at a 80's gym version here. Nothing fancy but more diverse and elaborate than most of the hotel health clubs.