I would say with the technology of todays hot tubs, it is less likely that someone would get a yeast infection, but on older style hot tubs very likely. Tubs of today are equipped with electronic controls, that turn on all pumps and air blower every 12 hours, even spas equipped with 24 hour circ pumps have this feature. So no stagnent air or water will lay in uncirculated water or air lines. With older tubs, without the automatic 12 hour blowout, yeast infections were actually quite common. Older tubs were equipped with time clocks, which did circulate water in water plumbing lines. The problem was not with the water plumbing lines, but with the air blower lines. If a spa owner went a week or two, without turning on their air blower, then water and air layed stagnent in the air channel line, causing bacteria to build up. Air channel holes or injectors of course are located on the seats. When the blower is turned on, the bacteria enters the water. Manufacturers reacted and developed electronic controls that blowout blower lines, while many top spa manufacturers eliminated blowers all together. Eliminating blowers and adding more jet therapy is a good trend. Air Blowers seem to cause more trouble, than good. They are loud, they bring in cold outside air and cool the water down, the check valves fail and the blower gets wet and trip the breaker, the air injectors in many cases crack over time. Dave.
