@Sonia-And-Luis0 Our hot tubs are 4 person, 280 gallons. We have had some for 20 years, others for less than 5. (We only have one listing currently on AirBnB). After multiple guests claiming that they were dirty, smelled of chlorine, caused rashes, etc., we changed our entire maintenance process and have had no more complaints relative to sanitary issues.
The fact that we advertise (and deliver) a fresh changeover of the hot tub water is a major selling point for our property over someone elses.
We do not do same day turnovers, so we have the time to empty, scrub, refill and treat the hot tubs. It takes 4-6 hours for the hot tub to reach a preset temperature of 101 degrees. (People do not pay attention to the recommended 15 minutes of immersion if it is set higher.) Because the water is changed for each guest, we do not have to use as many chemicals to keep the water clear. We also change out the filters with each guest; we keep 3 filters in rotation, soaked and cleaned in the manufacturer/seller recommended product.
How you choose to offer your hot tub is up to you. We have just found it expedient to be proactve rather than reactive. P.S. You would NOT believe what people will do in a hot tub.