How to remove rust from hot tub water

It almost does not matter how well you handle your hot tub, it will always get dirty over time. Cleaning will help to keep it in great shape. But getting stains out of your hot tub can be a challenge. Depending on the type of stain, there are different methods to remove it easily without damaging the hot tub.

How do I get stains out of my hot tub?

The first step to remove stains from your hot tub is to check the origin of the stain. If it is from organic material, use a mixture of white vinegar and water. The same mixture can be used for white stains. If you notice yellow stains due to mold, use Hydrogen Peroxide together with anti-mold spray. Different types of stains require different cleaning solutions.

In this blog post, I will explain what to do with certain hot tub stains. To make your work easier, I have differentiated the type of stains mainly on color. At the end of the post, I will explain how to get rid of stains on the hot tub shell. Do not forget to replace the water after cleaning.

Contents

• 1 Hot Tub Stains from organic matter
• 2 Removing white stains from your hot tub
• 3 Yellow stains on the hot tub
• 4 Cleaning Rust spots on your hot tub
• 5 Hair-dye stains in the hot tub
• 6 Scaling on the hot tub shell
• 7 What is the brown stuff in my hot tub? 
• 8 How do I get rid of brown stains in my hot tub? 
• 9 How do you remove stains from hot tub shells? 

Hot Tub Stains from organic matter

Generally, remove the hot tub stains caused by organic matter using a mixture of white vinegar and water. Apply the mix on the stained area and rub with a non-abrasive scrubber. Metal stains may not be removed this way. Ideally, you need to identify the nature of the stain on your hot tub to explore a way to remove it. 

To identify if the stain on your hot tub is due to organic substance or metal content in the water, examine its response to different cleaning agents. To ensure if a particular stain is from fallen leaves or similar organic matter, put a sock filled with Chlorine tablets on top of the stained area. If the stain gets lighter after some time, you may infer that it is organic residue. In such cases, use a vinegar-water solution to rub it off.

However, if the stain is due to metal content in the tub water or metal objects like a bottle cap left inside the tub water for days, it will not get lightened by Chlorine. To ensure it is a metal stain, you may place a sock filled with Vitamin C tablets on top of it. If it gets lightened after some time, it is a metal stain. 

In such cases, you may keep the hot tub water at 7.2 to 7.4 pH and add ascorbic acid or Vitamin C powder to it. Circulate it for two hours or so to remove metal stains from the tub interior.

Removing white stains from your hot tub

White stain is a common occurrence if your tub water has heavy minerals. In such cases, the calcium content in your water may lead to white build-up near the water level or in other parts of the hot tub. The permanent solution to this issue is to use water with low mineral content in your hot tub. 

These white stains are usually not very difficult to remove. Rub the stained area with a white vinegar-water mix using a wet, soft cloth. Rub the area in till the white stains disappear. Rinse the area with water and use a clean, soft cloth to wipe it again. Using soapy cleaning agents for this purpose may lead to foaming or suds in the hot tub water. Vinegar will get the work done and won't leave suds in the water.

Yellow stains on the hot tub

Yellow stains may appear in your hot tub due to several reasons. The presence of molds or certain other kinds of fungus may result in yellow stains. In such cases, using Hydrogen Peroxide to remove the stains is very effective. Treat the hot tub surroundings, and the cover with an anti-mold or mildew spray to eliminate mold growth.

Yellow stains also can be left by debris like leaves in an unattended hot tub. Such stains can be removed by Hydrogen Peroxide or even with some Dichlor treatment. However, do not use highly concentrated Hydrogen Peroxide for this purpose. Hydrogen Peroxide at lower than 3% concentration will usually get the job done. 

Alternatively, a one to two mixture of white vinegar and water may also work like a charm. In case the stain is difficult to remove, you may use some Magic Eraser to remove it. If you use Magic Eraser to wipe away the stain, ensure to rinse the surface with plenty of water after stain removal.

Cleaning Rust spots on your hot tub

You may come across rusty spots on your hot tub shell. These also can be treated with Vitamin C tablets. Rub it with a wet Vitamin C tablet, the stain will be removed. Mostly, these stains are caused by the presence of iron in the water. 

Baking soda is also effective in removing rust spots. It is very effective on fiberglass surfaces. Mix baking soda in water and pour it over the rust stain. Then use a cloth dipped in a vinegar solution to wipe it off. Rinse the area well with water after the stain removal. 

Hair-dye stains in the hot tub

Some bathers may leave hair dye stains in the hot tub. In such cases, it may be a bit difficult to remove it with just elbow grease. You may try using a white vinegar-water mixture to remove it. If it is not effective, you may use a mild detergent solution. Using either of them will remove any loose hair-dye present on the tub surface. 

If the stain remains, you may use isopropyl alcohol on the spot. It is better to apply some isopropyl alcohol to a small area to check for any adverse reaction. If it is effective, then rub the stain with a soft cloth after applying isopropyl alcohol. Rinse with water after the removal of the stain. If this is not effective, you may try Magic Eraser as a last resort. But ensure to wash it off with plenty of water.

Scaling on the hot tub shell

The use of heavy water in the tub may lead to scaling when the heavy mineral content in the water deposits on certain tub parts. Vinegar is an effective agent to remove such scaling from the tub parts.

What is the brown stuff in my hot tub? 

You may find brown stuff on the hot tub for several reasons. If you have not purged your hot tub for a long time, the gunk inside the plumbing may come out and stick on your hot tub shell creating brown stains.

Generally, the presence of oil, dirt, debris, and tissue cells from the skin of bathers may lead to brown dirt build-up on hot tub surfaces. But they are easy to remove with white vinegar.

In some other cases, the presence of high metal content in the hot tub water may leave brown or rusty spots on the hot tub shell. They are highly likely to appear if you are using well water with high iron content.

How do I get rid of brown stains in my hot tub? 

If the brown stains are due to dirt build-up, rubbing with a soft cloth would easily remove it. If the stain is in a difficult location, use a soft-bristled brush to rub it off.

In case of rust spots or metal stains, use Vitamin C tablets to rub the spots off. Please do not use harsh cleaners for stain removal as they may spoil the tub surfaces. Avoid using cleaning agents containing strong acid or base ingredients or harsh solvents. Similarly, do not scrub the tub interior with abrasive scrubbers like steel wool since it may cause irreparable damage to the tub surface.

Generally, isopropyl alcohol also can be used as a stain remover for organic stains, just like you would use White-Vinegar. However, it costs you more than vinegar. For removing scaling and for scum stain removal, baking soda can also be used. However, ensure to rinse well with water to avoid excess baking soda leading to further water spots.

How do you remove stains from hot tub shells? 

In cases where the stain is limited to the waterline or above, you may try to wipe them off by using a soft rag with a white vinegar and water mixture. Similarly, if your hot tub has only a couple of stains on the shell, you don't need to drain the tub in most cases. 

Try placing a sock filled with Vitamin C tablets or Chlorine tablets. It will remove mild stain spots created by organic or metal components in the tub water. However, cleaning agents like detergents may lead to suds in the water if you do not drain the tub.

An unattended hot tub filled with water of heavy mineral content may develop stains in multiple places. Sometimes an entire area in the tub may turn brownish or yellowish. In such cases, before trying to drain water and rubbing it off, I recommend adding Vitamin C powder (ascorbic acid) in the water. Let it circulate for some time. This way, it saves you the time and effort of trying to rub it off. Mostly, this will take care of metal stains caused by the metal presence in the tub water. 

Ideally, after the ascorbic acid treatment, you should add some sequestering agent to the water to break down the excessive metal content in it. The pH will be low for the water after adding ascorbic acid. Leave it so for a while and start rebalancing from the next day onwards. After removing the stains, you may replace the hard water with softened water with less metal content to avoid the stains reappearing.

The sticky gunk coming out of the innards of the hot tub may leave spots on the hot tub shell. I recommend purging the hot tub with Ahh-Some or similar plumbing cleaner agents to remove the nasties inside the pipework. 

After the purge, skim off the brown scum from the water level before it sticks and dries up on the shell, leading to more stains. Again, it would be best to wipe down the tub interior using a soft rag or sponge with a white vinegar and water mixture. You may also try Borax or Hydrogen Peroxide on stains which are difficult to remove. After rubbing the stains off the tub, you need to rinse it with plenty of water before filling it again.

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