All bodies of water release gases. Spas will release more fumes than most because the water is heated. Since most spas stay covered most of the time, this adds up to a fairly high level of harmless gases under the spa cover. When the cover is opened, these fumes are released and will sometimes cause throat and eye irritation and coughing.
To prevent a heavy odour, ventilate the spa room well if indoors. Periodically remove cover to release gases and prevent extensive build-up.
If the odour is musty or unpleasant, add Optimiser Plus. Leave the cover off for a few hours a day if possible. Clean the cover periodically with a disinfectant.
