Don't be upset. DH is a chemist and fully aware of 'nasties' that can occur in hot tubs etc.. Certainly in Hotels there are strict standards against Legionella and those offering B&B, AirB&B etc. should be emptying, cleansing and refilling - but that isn't very green is it! For home use it can be more relaxed and I believe that there are specific chemicals to add to the water?
Many years ago I used the Leisure Centre hot tub:once: it was noisy, I also felt that should someone disappear under the bubbles they wouldn't be found - I couldn't even see my toes!
