Deep Cleaning Your Hot Tub From Bacteria

You follow the rules and drain the water in your hot tub at intervals recommended by the manufacturer and local dealer. But the longer you own your hot tub, the more frequently you have to add chemicals and it needs to be drained. You used to be able to go a little over 3 months keeping the water balanced and clear. Now, around 2 months you have to add more chlorine than usual to keep the water sanitized and are draining and refilling just as often. You’re conscientious in following your chemical regimen, so why does the water seem dirtier the longer you own your spa?

Over time, organic waste like skin and hair cells, byproducts from disinfectants, oils, mold, mildew and scale accumulate within the spa pipes. If left untreated, this material can form a bacterial biofilm, which consumes sanitizer, causes odors when the tub is being used and reduces the efficiency of the circulation system.

Biofilm, or biomatter, is a protective layer created by bacteria. The bacteria secrete a plastic-like substance called EPS (extra cellular polysaccharides) that forms a slime layer around the bacteria cells and binds them together.

In a 2010 paper published by Harvard University scientists entitled “Bacterial biofilm shows persistent resistance to liquid wetting and gas penetration,” the authors note that: Biofilm formation is now known to cause contamination of plumbing, oil wells, medical implants, building heating, ventilation, air conditioning and other systems and is largely responsible for nearly 100,000 nosocomial deaths annually in the United States and 80% or more of all microbial infections in humans.

Unfortunately, the Harvard study found these biofilm formations were difficult to penetrate, and when treated with biocides like chlorine and other antimicrobials, live cells were still found within them.

In a portable hot tub, you are most likely to find biofilm in the plumbing, but it can also form on the tub surface and filters. When you simply drain your tub and introduce oxygen to the pipes, this actually helps the bacteria to grow even faster. Since you can’t see biofilm in the pipes until you’ve flushed it out, you and even your hot tub dealer sometimes don’t realize it’s a potential problem — it’s hidden away.

If you keep your water perfectly balanced with the proper amount of sanitizer at all times, no biofilm should ever form. However, that’s not always possible. If you have more people use the tub than usual, are out of town or simply forget to add the appropriate chemicals for a few days, bacteria will take the chance to bloom.

If you let your hot tub water go for up to three days without any disinfectant, the bacteria will multiply rapidly, creating biofilms in your plumbing and in the water circulation in the spa. Once a biofilm colony forms in the plumbing, you can continue to treat the water to kill bacteria and not have any ill effects, but the biofilm are hiding or keeping dormant some of the bacteria that was in the water. The biofilm is a harboring place for bacteria, and as soon as the conditions are ripe the bacteria will use that opportunity to spread. If you ever forget to sanitize your water, or, for whatever reason, don’t keep the proper parts-per-million of your sanitizer, the bacteria will become mobile very quickly.

But if sanitizers like chlorine can’t effectively penetrate biofilm-like the Harvard study found, how do you get rid of it? There are multiple approaches, with many companies now offering products that dislodge and flush all contaminants, including biofilm, out of the system. This is often called a purge.

The next time you need to drain your spa, try a product like Ouster Hot Tub Restoration, Hot Tub Serum or Ahh-Some Jet Cleaner. Empty the bottle or packet into your spa water, turn the jets on high and circulate the product in the water for about 20 minutes. And just watch the junk come out. If you had a biofilm buildup you can expect to see brown foam start to form on top of the water, with black specs and globs coming out of the jets and floating in the water. When the time is up, drain your tub and wipe off all the gross junk from the surface of your hot tub.

Once you’ve seen what comes out of your plumbing, it’ll be obvious why you were having a hard time keeping your water clear and balanced. Now, when you refill your tub, you should be able to enjoy that freshwater for the recommended amount of time. Generally speaking most hot tub service techs recommend purging your hot tub or swim spa 4 times a year (quarterly) unless a problem is persistent.

Any time you have water circulating in a closed system where oxygen can be introduced, biofilm will most likely form. It’s not just hot tubs — jetted bath tubs, dishwashers and washing machines are all home appliances that you’ll eventually need to purge from the inside out tonot only clean but keep running at peak efficiency.

A good rule of thumb to determine if your spa is ready for new water is to use this simple method: divide the spa gallonage by three. Then divide this result by the average number of bathers per day. The final results are the estimated number of days between water changes for a properly maintained hot tub. For example, a 600-gallon spa divided by three equals 200. If the spa averages two users a day, 200/2 = 100 days between refills.

Hot tubs require frequent testing — at a minimum you should test your water using test strips weekly. You should test the sanitizer level before each use of the hot tub. As soon as people get into the tub, they begin to deplete the sanitizer level — and it can deplete quickly. It is important that you prepare the water for this by setting the sanitizer at the appropriate level before use.

Total alkalinity and pH levels can also fluctuate quickly because of the small volume and quick reactions due to high spa temperatures. Therefore, you should test these parameters at least twice a week.

Total dissolved solids is one other parameter that you should check on a routine basis. TDS is the buildup of everything that you add to the water (chemicals, organic waste, fresh water, etc. all contain dissolved solids). TDS can build up quickly in a hot tub primarily because you are adding fairly large doses of chemicals to a small volume of water. Measuring the TDS level can give you an indication of when it is time to drain and refill your hot tub.