The spa is something I've never tried before, but I suppose it's akin to a Turkish bath or Russian Banyo, but with less man-on-man time, and more swimming in various pools. Since the Chinese are big on different medicines there are hot tubs with some medicines like Ginseng, Red Wine, Gegen （葛根) or Kudzu, 当归 （dang gui），or Angelica Cutiloba, and what they said was lavender, but it looked like purple food coloring.
One of the things we tried was the Doctor Fish or Garra Rufa treatment, which uses small, toothless fish that suck dead skin off of your body to eat. It tickles quite a bit, and I'm not sure that it really does anything other than expose your feet to fish poop, but it was interesting to try.
Also in the building they had various swimming pools for both lap swimming and kiddie pools. It's a really nice experience that I recommend trying sometime!
You see, Chinese babies don't use diapers, they just go out slits in their onesies.
For me it would be worth it, because the spa is awesome.