We don’t mean, are you sharing your spa with a friend. We mean that there are dangerous chlorine-resistant microorganisms that can invade spa water under some circumstances. As unusual as this may be, you need to be aware of the threats, and what you can do to prevent the threat.

Tests have found that chlorine in swimming pools works so slowly against Cryptosporidium parvum, for example, that it is not considered an effective disinfectant in that case. The Center for Disease Control is actually in the process of developing guidelines called the Model Aquatic Health Code to address this kind of chlorine failure in public swimming venues.

However, we think you need to know that under some circumstances, these dangerous ‘bugs’ might infect your spa. In this post, we want to introduce you to the parasite Giardia.

Giardia lamblia – An Unwelcome Guest

Like crypto, giardia is a microscopic parasite whose spores, which live in the intestines and are passed in fecal matter, can infect humans. The resulting disease, called giardiasis, is a diarrheal illness accompanied by diarrhea, abdominal cramps, dehydration and other unpleasant symptoms. Giardia may be present in untreated or undertreated water of all kinds, from natural streams to pools or hot tubs.

Causes of Giardiasis

The proximate cause of giardiasis is when the giardia cysts are present in fecal matter polluting the water body and swallowed by a bather. We understand that this sequence is very unlikely to occur in your hot tub, but there are some unusual circumstances where it might occur. Here’s a statement from the California Department of Public Health about sources:

Persons at increased risk for giardiasis include children and staff in day care centers, international travelers, hikers, campers, swimmers, and others who drink or accidentally swallow water from contaminated sources. Persons who have unprotected anal sex are also at increased risk of contracting giardiasis.

Lots of families love to share their hot tub. If they happen to have a baby or young child in diapers, for example, they may be more at risk of giardia infections.

Ozone Kills Giardia Better than Chlorine

Even though the risk is very small, the fact is that hot tub owners can get better protection against giardia with ozone than with chlorine. Again, from the CA Department of Public Health (same page):

Anyone with giardiasis should avoid swimming pools. Giardia cysts are resistant to chlorine levels used in swimming pools and are passed in the stools of infected people for several weeks, even after they no longer have symptoms.

Keep that ozonator working properly on your hot tub.