Hot Tub Supply Spa Depot
Spa Microbiology 101
Healthy Hot Tubs
 SpaCyclopedia Index Sanitizers Compared Decontamination Glossary

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The world over, hot tubs provide a delightful, safe and healthy experience for millions of people every day. If your spa is kept clean, balanced and sanitized, it can provide the same for you. We'll discuss spa sanitation problems and their easy prevention.

The Hot Water Environment

Dreammaker spas The same factors that make our spas attractive to us: warm, wet, and bubbly, can also make a poorly maintained hot tub attractive to microbes. Some of these can make us sick. Hot water opens our pores and allows microbes an easier route to possible infection. We can inhale contaminated water droplets made airborne by the spa jets.

Hot tubs are not small swimming pools.

Due to their warmer water temperatures, lower water volume, and higher bather loads, a little extra care must be taken to properly maintain hot tub water quality. Maintaining a healthy spa is really quite easy, takes just a few minutes out of your busy schedule, and will help prevent problems.

Our Natural Defense

Natural defense Our bodies provide an amazing resistance to disease. We are constantly exposed to microorganisms all around us, yet we rarely become ill.

Most problems with environmental microorganisms can be prevented by appropriate maintenance and monitoring of the spa. This is why sanitizing and shocking, water balance, as well as keeping surfaces and spa filters clean is the best defense against infections or other problems.

Your Nose Knows!

So how do you know if your water is healthy and properly sanitized?  Fortunately, we have spa test strips to monitor sanitizer and water balance levels, as well as a bacteria test.

Amazing human nose Each of us is equipped with a very sophisticated test instrument: our nose! (Many of us have used this device to test milk from our refrigerators for freshness).

So if the spa water smells foul or sour, it likely has problems. Trust your nose, test your water, choose a good sanitizer, and monitor it. If you are new to this, take a few moments to read our ABCs of Water Chemistry for a good basic understanding. Regular use of Spa System Flush will help clean your spa's plumbing system from the inside. Make it part of your regular spa maintenance routine.


microorganisms There are several types of microorganisms, which can grow in spa water: bacteria, fungi, protozoans, and viruses.  We use sanitizer systems to eliminate and prevent them.

Some of these are pathogens, which can, under certain circumstances, cause disease. These organisms can come from a variety of sources including other humans and animals, from the ground, from water or even airborne sources. In a poorly maintained spa they can form biofilm in the plumbing system, on surfaces, and in nooks and crannies. Left unchecked, they will rapidly multiply.

Culprits include various forms of Pseudomonas, which can affect ears, eyes, skin (rashes) and the respiratory tract. The microorganism that causes Legionnaire's Disease is commonly found throughout our environment, particularly in soil. It can thrive in warm water where sanitizer level is inadequate, and has been known to become airborne via the action of the air jets in spas. Another is Mycobacterium avium, which can cause flu-like symptoms.

Interestingly, researchers have found that many people who complain of "allergic reactions" to sanitizing chemicals are actually suffering from skin rashes caused by bacteria due to inadequate sanitizer levels!

More about Pseudomonas

Hot Tub Folliculitis is a is a condition caused by Pseudomonas bacteria, and is often seen where spa sanitation is at fault. The most common symptom is an itchy rash or small reddish bumps, sometimes confused with bug bites. It can develop into more serious problems. This condition usually clears without scarring. It may recur if the infected hot tub is not properly cleaned and disinfected. Contact your health care provider if you develop symptoms*.

Two Types Pseudomonas Outbreaks

  • The most frequently seen kind is called transitory Pseudomonas contamination. In roughly 15% of the population, Pseudomonas is a naturally occurring organism on the skin. When a heavy bather load (such as a party) occurs in the spa, all the sanitizer may be temporarily used up. This gives the organism an opportunity to spread from the carrier to others in the tub. Once the bathers leave the water, the spa's disinfectant residual can be re-established, killing the organisms before they can set up a more lasting residence in the spa.
  • The second kind of outbreak occurs when Pseudomonas has been allowed to set up residence in the spa. If the sanitizer residual falls too low from neglect, or is not re-established soon after a heavy bather load, the organism can set up residence in the water, on surfaces, on the filter(s), and in the spa's plumbing system. It can even infect a dirty or waterlogged spa cover. The longer the sanitizer is neglected, the worse this problem can become. This is because once it sets up residence, Pseudomonas covers itself with a slime layer or biofilm which shields it from the sanitizer. Fortunately, we have good methods to deal with resident contamination and biofilm removal.

Hot Tub Folliculitis Indicators:

History of using hot tub within last three days
Itchy, bumpy, red rash appearing within 2 days of hot tub exposure
Bumps may develop into dark red tender nodules
May develop small blisters
Multiple members of family or party with same rash and same hot tub exposure

Contact your physician for medical advice immediately
if you suspect an infection.

*Note: Although your doctor is an expert on human conditions, he may not necessarily have training on the sanitation of spas. If you're having recurring or persistent problems with contamination, please read Hot Tub Decontamination Procedure.


Following these basic procedures will help prevent problems:

  • Start out with cleaner water. The Prefresh Spa Fill Filter attaches to your garden hose and provides purified filling water.
  • Encourage good hygiene. A shower prior to use is a good practice.
  • Monitor bather load, adjust water ph & Total Alkalinity, and drain spa when necessary.
  • Avoid using spa when wounds or open cuts are present.
  • Maintain adequate sanitizer level at all times. Check bromine or chlorine before each use with test strips; alternately, maintain Cleanwater Blue or Nature 2 per package instructions.
  • Shock treat regularly with OxySpa monopersulfate to effectively oxidize contaminates.
  • After heavy use of the spa, or when smelly or cloudy water is noticed, shock with dichlor to quickly clear up problems.
  • Maintain proper pH level to optimize sanitizer effectiveness.
  • Test your water frequently using spa water Test Strips.
  • Keep waterline and adjoining surfaces clean.
  • Clean filter regularly with a commercial cleaning compound such as Eco Soak or Power Soak. Replace annually. Filter Replacement Guide
  • Thoroughly clean spa at each drain/refill. Don't forget to clean your spa cover, inside and out. We recommend the use of an effective non-foaming, pH neutral product such as Clean All, which will not alter water chemistry.
  • Prior to each draining, use Spa System Flush to rid your plumbing and heating systems of grime, oils, dirty buildup, etc.
  • If your spa cover is smelly and in poor condition, replace it. Why? A contaminated and waterlogged spa cover can continuously inoculate your spa water with microorganisms, not to mention waste energy dollars.
  • For recurring problems, refer to Spa Decontamination Procedure.

Spa Vac

You'll probably want one of these!

The Shake-a-Vac self-priming spa drain and vacuum will help you keep a cleaner spa by removing grit and debris.

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Clarathon Spa Filter Cartridges

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