hot tub 
noun
A large tub filled with hot aerated water used by one or more people for recreation or physical therapy.Drain water from pools, hot tubs and roof drains to a ditch or separate dry well....
- The two police officers slowly approached the hot tub filled with blood mixed water.
- Do not expose your tattoo to direct sunlight, tanning beds, saltwater, pools, saunas and hot tubs for 2 weeks.