How To Remove Iron From Hot Tub Water?

How To Remove Iron From Hot Tub Water?

Having a hot tub is a blessing, as it allows you to have a body and mind-refreshing hot soak whenever you feel like it. But it requires a similar kind of maintenance and care effort to keep your hot tub up and running. There can be tons of issues with your hot tub or the water in it. Iron in your hot tub’s water is one such issue that needs to be dealt with frequently. You wouldn’t want to let these irons damage your hot tub or put stains on your clothing.

If you have a similar issue with having irons in your hot tub, then you have come to the right place. There are several ways you can remove these nasty-looking irons from your hot tub. In this article, we will give you a detailed solution to some of the most effective ways to remove iron. We will also cover your similar queries, such as if irons are harmful, how you can identify them for removal, and lastly, how you can prevent their coming.

5 Ways To Remove Iron From Hot Tub Water

Ways To Remove Iron From Hot Tub Water
Ways To Remove Iron From Hot Tub Water

There are quite some ways to remove iron from hot water. You can use any one or mixed iron removing methods upon identifying irons in your hot tub.

1. Install an Iron Filter

The first battle against iron in your hot tub should start with installing an iron filter. Almost all hot tubs use a default filter. These filters may not be enough to deal with small iron particles (less than 3 ppm). In that case, you can install a specific iron filter that focuses more on filtering iron along with other operations. The filter should be installed in line with your hot tub’s plumbing and allow the water to circulate through it. If not altogether, this filter will suck out the iron each time you splash or change the water.

Application Steps

  • Turn off the hot tub and drain all the water.
  • Remove the filter cartridge from your hot tub.
  • Install the iron filter in line with your hot tub’s water line.
  • Reinstall the filter cartridge.
  • Refill your hot tub with fresh water.
  • Turn on the power supply to your hot tub.

2. Use An Oxidizer

One of the best ways to remove iron from your hot tub is by oxidizing. It is a chemical-based process that allows you to inject more oxygen into your hot tub’s water and remove non-bacterial contaminants such as iron. There are two types of oxidization: chlorine-based and non-chlorine. Oxidization creates a reaction in the water that breaks down iron and other solid contamination molecules and helps them get removed upon shock. It also helps to retain the water’s neutral pH level, which gives it a fresh vibe. Based on your tub’s setting, you can either use liquid or solid oxidizer tablets.

Application Steps

For using the liquid oxidizers:

  • Take a glass jar and put some water into it.
  • Pour oxidizers into the glass using a tablespoon. (Amount per 1500 liters: Non-chlorine= 7gram & chlorine based= 35gram.)
  • Gently mix the elements for a while.
  • Pour the glass’s mixed water into the hot tub.
  • Shock the hot tub for at least 20 minutes before using it.

For using solid tablets:

  • Detach your spa’s chemical dispenser chamber.
  • Place 1 or 2 oxidizing pills into the dispenser.
  • Reinstall the chamber into the designated place.
  • Shock for 20 minutes before using the tub.

3. Use Metal Sequestrant

A metal sequestrant, or sequestering agent, is a chemical substance containing molecules able to bond with metal ions to form chelate complexes. They are mostly used in pools due to the heavy metal congestion. Meaning they are highly effective in removing such a small amount of metal from your hot tub. Sequestrants are used to bind to metal ions dissolved in water and prevent them from depositing as stains.

Application Steps

  • Pour your desired flavored metal sequestrant into the hot tub.
  • Leave it overnight and let it dissolve the irons.
  • Read the user manual regarding the amount of application before applying.

4. Drain The Tub

One of the hassle-free and more assured solutions to your hot tub’s metal problem is draining the water. It allows you to have a fresh start over again and let hot tubs and other water-related issues get a pause. After all, no water means no irons for a while. Although you need to check all the hot tubs functioning before refilling fresh water into the tub, Don’t forget to clean your hot tub surface thoroughly to remove any stains and iron surfactant to prevent contaminating the new water.

Application Steps

  • Splash or normal shock your hot tub water to mix the irons into the water.
  • Open the drain valve and let the water drain as fast as possible.
  • Clean the tub with detergent chemicals.
  • Use a brush, and cleaning fabric to scrub the surface if needed.
  • Rinse thoroughly with fresh water.
  • Repeat the method several times until satisfaction.
  • Refill the tub with fresh water.

5. Vinegar-Soda For Stains

It is not the layer of iron that always bothers you. Having metals in your hot tub can ultimately put stains on the water taps, tub floor, water line, and water drainage vent. For removing such stains, you can use DIY solutions such as vinegar and soda mix. These two substances are easily found in almost all kitchens and are known for effectively removing hard stains. To remove stains beneath the water line, you should drain the water first.

Application Steps

  • Mix equal amounts of water, liquid vinegar, and 1-2 spoonfuls of baking soda.
  • Apply the mix on stained areas and let it react for some time.
  • Scrub the stained areas with a rag or mild scrubber.
  • Beware of scrubbing pressure to avoid damaging the tub.
  • Repeat the method more than once for better results.
  • Rinse with fresh water or wipe with a damp rag.

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Is Iron In The Hot Tub Water Harmful?

Is Iron In The Hot Tub Water Harmful?
Is Iron In The Hot Tub Water Harmful?

There is not much evidence that the iron in the hot tub water is harmful to the human body. The most harm it can cause is leaving stains in your bathing suit. On the other hand, irons in the hot tub water harm the very container and your hot tub in the process if they are in great numbers. Some of the negative sides of iron in hot tub water.

  1. Causes of pH Imbalance: The basic standardization of your tub’s water safety margin is its pH level. Having iron in your hot tub’s water creates buildup. This contaminated buildup alters the pH level of the water from neutral to imbalanced.
  2. Water Gets Color Disoriented: Too much iron in a hot tub can disorient its overall color. Iron in the water is a reddish brown color, and similar types of metals such as copper and magnesium cause the water to be discolored. Everybody may not feel comfortable soaking in such water.
  3. Corrosion in a Hot Tub: Remember, iron and corrosion are two interconnected terms. In most cases, iron enters your hot tub through corrosion in the water line. These can also corrode the shell, the jets, the headrests, and even the filters in your hot tub.
  4. Higher Maintenance: There could be more than one reason why your hot tub’s water has iron. It may take some chemicals, parts replacement, and maintenance to solve this issue permanently. This higher maintenance means higher costs all around.
  5. Stain Everywhere: As mentioned earlier, irons can stain very easily if they are in great numbers and left for a long time. This can cause stains and damage your dress and your lovely hot tub.

How To Identify Iron In Hot Tub Water?

How To Identify Iron In Hot Tub Water?
How To Identify Iron In Hot Tub Water?

Identifying irons is not that hard if you know what to look for. Some of the symbols of your hot tub’s water are irons:

  • Layer of Colored Substance: The first clue you will get is the visual appearance. Usually, ferric iron is reddish-colored. But it can turn yellow or brown from time to time. You will see layers of such iron just above the tub’s surface.
  • Water Color Changing: If not visually noticed, iron in the water gets identified through the water’s distinct color transformation once cleaning surfactants such as chlorine and bromine are added to it. You will see your tub’s water turn green if it has iron in it.
  • Stain Mark: The most reliable proof that your tub’s water has iron is the stain marks left by it. This rust-like stain takes time to build but is a definite indication that your water has iron.

Preventing Irons From Growing In Hot Tub Water

There is a phrase that says prevention is better than cure. It also applies to iron in your hot tub water. You can take these preventive measures to reduce iron in your tub’s water.

  1. Change The Iron Filter: Almost all hot tubs usually come with a built-in filter. You need to keep an eye out to see if your water filter is able to block the iron from coming. If it fails, then immediately replace it with a better version of it.
  2. Use Water Softener Periodically: Use your desired form of water softener on a routine basis. You can use a salt-based softener, as salt-free conditioners don’t impact iron.
  3. Check The Plumbing Line: The plumbing lines that supply water into the tub are metal and prone to corrosion. Check your plumbing pipes for signs of such metal corrosion. Replace if it seems needed.
  4. Refill Tubs Water Routinely: To prevent irons from growing in your hot tub’s water, changing the old water with new ones every now and then is the most effective way. Refill the tub based on your intensity of use.
  5. Inspect The Water Source: The water source is one of the major factors in supplying iron to your hot tub. For example, well water contains a severe amount of minerals and elements. This includes iron, copper, magnesium, and such metals.
  6. Cover When Not In Use: You will be surprised to know that air is also a formidable source of iron in your water. Industrially polluted smoke containing such metals can easily contaminate your tub’s water. So it is better to cover your hot tub when not in use.


1. How do you remove metal from hot tub water?

You can use any of the Reverse Osmosis (RO) added water purifiers to get rid of brown water in your hot tub. The semipermeable membrane used in RO technology prevents pollutants bigger than 0.0001 micrometers from passing through while allowing water molecules to flow freely.

2. How do you know if your water is making you sick?

Being exposed to or consuming polluted water is one of the easiest ways to get sick. If you think your tub’s water is making you sick then look for pollution in it such as water being cloudy, bad odorous, brown or orange hue, metallic taste, etc.

3. How do heavy metals in water affect humans?

Although it is not found that small iron particles are harmful to humans, heavy metals in water can surely harm you. People exposed to continuous heavy metals consumption can get affected with acute and chronic toxicity, liver, kidney, and intestinal damage, anemia, and cancer.

Final Thoughts

Irons in the hot tub water aren’t a matter of concern until they rise in great numbers. They may seem innocent at first glance, and to tell you the truth, they don’t really harm human bodies directly. But iron should be removed from the tub’s water. Because they are annoying to see, they can damage your hot tub and put stains on your clothes. Cleaning these irons is pretty easy if you know what to do. So next time you see such irons in your hot tub, no need to panic. Use any or more of these simple methods to easily clean the iron and keep your hot tub shiny. Don’t forget to find their source and take preventive measures to block their return as well.

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I am Donald M. Beyer and I am backyard enthusiasts. I am a homeowner who has been doing DIY projects in and out of my house for many years. From simple backyard lunches to making an old-school pizza oven in my own backyard, I have a lot of experience in turning my backyard into my and my family’s personal playground.

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