Why Does My Hot Tub Smell? Expert Advice to Remove Obnoxious Hot Tub Smells | O-Care Spa Care

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Why Does My Hot Tub Smell? Expert Advice to Remove Obnoxious Hot Tub Smells | O-Care Spa Care

"Why Does My Hot Tub Smell?" is a question many hot tub owners find themselves asking. Unpleasant odors from your spa are not just a nuisance; they signal underlying issues. Whether it's a musty, chemical, or rotten smell, each type hints at different problems.

Various factors can contribute to this common issue, from improper chemical balance to bacteria build-up. This article aims to uncover the reasons behind smelly hot tub water and offers practical solutions. Understanding what causes these odors is the first step to enjoying a fresh and inviting spa experience once again.

What Causes Hot Tub Water Smells?

The warm environment of hot tubs is a breeding ground for bacteria that can cause bad smells. With regular maintenance, you can ensure your spa water and filtration system can prevent a pungent smell.

Hot tubs with smelly water often result from:

  • Low sanitizer levels
  • Inadequate pH management
  • A dirty spa filter.

If your spa water smells bad, like chemicals, the water chemistry may have too much sanitizer, such as chlorine.

What could cause your hot tub water to smell bad? Here are the most common causes:

  1. Your water chemistry is off: either the pH level is too high or too low, or the sanitizer or hot tub chemicals are not right.
  2. There is biofilm in your spawater.
  3. Sediment or bacteria built up in your hot tub cover, filter, or pipes.

1. The Hot Tub Water Chemistry Isn't Right.

You need to understand your proper water chemistry. Many people don't realize that the pH levels of their spa water can affect how the water smells. When the pH level is too high, it doesn't mean there is "too much chlorine" in the water. Instead, a high pH level reduces the effectiveness of chlorine as a sanitizer.

Chlorine's ability to kill bacteria and sanitize effectively decreases in higher pH levels, potentially leading to under-sanitized water, not an overabundance of chlorine. If the pH level is too low, there won't be enough chlorine in the water, and it will smell dirty.

If the water is smelling, then in most cases, you are smelling contamination due to low chlorine.

Fix Sanitizer Levels to Rebalance Water Chemistry

Understanding when to use non-chlorine shock versus chlorine shock is key to maintaining optimal water chemistry in your hot tub.

Non-Chlorine Shock

Non-chlorine shock is excellent for breaking down organic materials such as oils and sweat, which can contribute to water cloudiness and odor. It oxidizes these contaminants, making it easier for the sanitizer to do its job. It's important to note that non-chlorine shock does not have sanitizing properties itself—it won't kill bacteria or algae.

You can use a non-chlorine shock that will break down oils but will not kill bacteria or contamination. This helps the chlorine work better, so it works great in conjunction with chlorine.

Chlorine Shock

Chlorine shock (calcium hypochlorite) is a powerful sanitizer that eliminates bacteria and other pathogens, ensuring your water is safe for soaking. It acts quickly to disinfect water, but its levels can diminish rapidly, especially if the water is heavily contaminated or if the shock is not added in sufficient quantity.

If we assume that you are using a sanitizer (chlorine or bromine), it is clear that it is not working. If you are not using chlorine at all, it would be advisable to use chlorine shock. This type of chlorine works fast, but it can be gone quickly, too, if you have not used that specific sanitizer. 

Add a small amount of hot tub shock and then measure. Most of the time, we notice that people will have to use more. The extra chlorine will dissipate within some minutes to an hour sometimes faster.

Don't worry about using some more because it will kill off contamination in the hot tub; that is perfect. Otherwise, it would be the opposite, and you should measure it.

You need to check and measure the free chlorine in your hot tub after some hours to be sure you are getting the right levels.

How to Fix the Water Chemistry

Check the pH and sanitizer levels if the water in your spa or hot tub water smells bad, musty or stale. Most of the time, we notice that you'll find that at least one of these is not correct. Use a pH test kit, chlorine test strips, or a digital hot tub tester to check the levels and adjust as needed.

  • When the pH level is off, most sanitizers won't work correctly. 
  • Set it between 7.2 and 7.8 and then correct the sanitizer value.
  • Run the pumps and wait a little while. The problem will most likely be solved.
  • At the proper pH levels, don't be afraid to use more sanitizer than usual. There is probably a small amount of contamination that needs to be dealt with.
  • Sometimes it can also be the filter that caused the clean smell; you should replace it regularly. ‍

2. There Is Biofilm in Your Hot Tub Water.

If you've noticed that your spa water isn't as crystal clear as it used to be, you likely have biofilm in your water. Biofilm is a narrow and thin layer of bacteria and other organisms that forms on the surface of your hot tub.

While biofilm is not harmful, it can lead to the overgrowth of harmful bacteria and other contaminants. You can take a few easy steps to get rid of biofilm in your hot tub.

For more information, be sure to read our guide on how to fix biofilm or other contamination. This will help you achieve successful decontamination. ‍

3. Sediment or Bacteria Build-Up in Hot Tub Covers, Filter, or Pipes.

Most hot tub owners have, at some point, experienced unpleasant smells that come along with the hot tub water experience. These smells can be downright obnoxious, but there are ways to take care of the problem and remove those smells for good.

Hot Tub Cover

It's important to keep your hot tub covers clean to prevent sediment or bacteria buildup. Here's how: rinse your spa cover with cool water using a garden hose. Spray with a gentle, non-foaming, pH-neutral cleaner (we recommend Simple Green) and wipe clean. For stubborn dirt, use a non-abrasive sponge. ‍

Hot Tub Filter

If you want to keep your hot tub water clean and clear, it's necessary to clean your filter regularly. A buildup of sediment or bacteria can quickly contaminate the water. Here are some tips for how to clean your hot tub filter:

  • Spray the filter with a hot tub filter cleaner once a week. Be sure to rinse it afterward.
  • Soak the filter in chemical cleaner every time you drain and refill your hot tub. This will help extend the filter's life and loosen any stubborn particles. Again, be sure to rinse it thoroughly afterward.
  • If you see that your filter is starting to deteriorate, replace it immediately. A worn-out or damaged filter can't do its job properly, leading to dirty hot tub water. ‍

Read more here: How To Thoroughly Clean Your Hot Tub Filter

Hot Tub Pipes

If your hot tub isn't draining properly, it could be because of a buildup of sediment or bacteria in your pipes. To clean your pipes and extend the life of your filter, soak the filter in chemical cleaner every time you drain and refill your hot tub.

Rinse the filter thoroughly afterward. You can also spray Filter to Clean on your hot tub filters, rinse your filter with water, and then your filters will going look brand new in less than 20 minutes! ‍

Proper maintenance is the key to defeating the bad smell

Regular hot tub maintenance is the key to making sure your water stays clean. That means checking the chlorine levels in your water regularly and adding sanitizers as appropriate. Every few weeks, fresh water should be added.

O-Care Spa Care transforms hot tub maintenance, directly addressing unpleasant odors at their source. It reduces the need for harsh chemicals like chlorine and bromine, cutting down on chemical smells.

Our product prevents biofilm buildup, eliminating a primary source of bacteria and odor. It makes spa water not only odor-free but also gentler on the skin and environmentally friendly. With O-Care, users enjoy clean, refreshing hot tub water without the hassle.

Here are additional resources to ensure you're always up to and keep the water nice and clean.

  1. Download the O-Care app for weekly maintenance and step-by-step problem-solving.
  2. Use our online water assistant to diagnose your water quality issues.
  3. This article covers more situations if the app didn't help solve your problem.
  4. I need to solve an underlying contamination issue in my hot tub; maybe it's biofilm?
  5. How to avoid future problems and keep your hot tub clean?
  6. What kind of sanitizers can I choose from?
  7. What is the best way to maintain my spa water?
  8. How to test the water in my hot tub?

Wrapping Up Our Expert Advice on Hot Tub Water Smells

Odor-causing bacteria can be defeated with the right tools and a little elbow grease. If your spa water smells, don't despair! The source of the smell is likely something that you can fix yourself if you have the right information.

And remember, if all of this sounds like too much work or you just want someone else to take care of it for you, we've got your back. Buy O-Care today from your local dealership and let us take care of your smelly hot tub so that you can relax and enjoy it again without worrying about the funk.

FAQs about Hot Tub Water Smells

Should my hot tub smell?

It shouldn't, but yes, it can be that your spa water smells bad. Many hot tub owners complain when you open the cover after it has been used because of the biofilm built over time on the surface of objects in the water.‍

Why does my hot tub have a weird smell?

There are a few reasons your hot tub has a weird smell. It might be coming from the water; this is a sign that your hot tub hasn't enough sanitizer in the water, the pH levels are off, or biofilm is building.

Why does my spa smell so strong?

Hot tub smells can be caused by various factors, including bacteria, algae, and dirt buildup. If your hot tub water smells bad such as too many chemicals.

How do I get the chemical smell out of my hot tub?

There are a few ways to get the chemical smell out of your hot tub. You can soak the filter in chemical cleaner every time you drain and refill your hot tub, or you can spray water from your garden hose on your hot tub filters.‍

Should you be able to smell chlorine in a hot tub?

No, a strong chlorine smell indicates too much chlorine in your spa water.

Why does my spa or hot tub smell like ammonia?

Ammonia is a typical odor in hot tubs because of the high levels of bacteria present.‍