How to Fix Yellow Hot Tub Water Quickly

The water in the hot tub must be clear. But it sometimes happens that the water turns yellow. Why is that, and how do you fix the problem?

The yellow water in the hot tub must be cleaned by adequate filtration and the use of a hot tub shock. After that, the water balance must be re-established. Alternatively, a small hot tub can be emptied, the surfaces cleaned and refilled.

In this article, I’ll explain why the water in the hot tub turns yellow and what you can do about it so that it doesn’t happen again in the future.

Why is the water in the hot tub yellow?

You might have experienced it when you lift the hot tub cover, only to see a color other than clear blue in the water.

When the conditions aren’t ideal, hot tub water can turn to any of the colors of the rainbow: yellow, green, and any shade in between.

The following are some of the reasons why the water in your hot tub may appear yellow: 

  • Yellow algae: This is a callous type of algae that can survive in the dark and heated water even with normal bromine or chlorine levels. It thrives in small spaces where they try to hide and multiply. It will deposit itself in sheets across the tub surfaces when fully bloomed. 
  • Pollen excess: In the spring, a bunch of pollen can cause yellow hot tub water. This is especially true if you haven’t used your hot tub in a while. 
  • Effect of Iron oxides: Iron oxides can also give the water a yellowish tint, which is most evident when the hot tub becomes yellow after being shocked. 
  • High bromine or chlorine levels: When bromine levels are incredibly high, the water can turn yellowish-red, especially when pH levels are low. If the bromine residue in a hot tub exceeds 5 ppm, don’t use it.

How to fix yellow water in the hot tub?

The following steps can be followed to resolve the issue of yellow water in the hot tub: 

1. Make sure your filter is working properly

This is the first place you should go if you have a water quality problem, especially if the water in your hot tub is yellow. It is quite difficult to solve the problem if some particles are not picked up by the filters.

2. Check the water balance levels

The water balance is your next stop. A common clarity problem can be caused by high sanitizer levels.

Check to see if the pH (7.2 – 7.6) and alkalinity (80 – 120 ppm) are correct, and make any necessary adjustments.

3. Check the disinfectant content

When there are high amounts of bromine or chlorine, the best treatment is to stop adding more until the levels drop.

Chlorine/bromine, on the other hand, is difficult and time-consuming to remove chemically from water, so it is best to let the ‘bank account’ you’ve built up naturally deplete.

You should remove the lid of your hot tub to expedite this process.

The bromine/chlorine can evaporate/escape the hot tub, thereby lowering the levels by removing the hot tub cover.

If this isn’t fast enough, dilute the mixture with water, this will help lower the bromine level to the recommended range.

4. Scrub the hot tub

The dirt needs to be loosened and filtered.

Start the filter and scrub the hot tub as best you can – a shock treatment alone is not enough.

5. Shock the spa

Using a non-chlorine shock, you can usually clear the water quickly without having to use a lot of sanitizers. The shock will remove the particles and, in most circumstances, solve the problem when used with a clean filter. 

6. Use a clarifier

A product like Spa Sparkle works similarly to a flocculent.

It clumps all the small particles together so that they can be filtered, which may help the water become clear. 

7. Deplete the spa

This should only be used as a last resort.

Drain the hot tub, flush the system with a pipe flush, and start over with fresh water if you possibly determine you’ve lost the battle.

This is sometimes the best option, especially after a period of heavy use (for example, a hot tub party!). 

Why does the hot tub water turn yellow after adding chlorine or bromine?

When too many minerals are combined with chlorine, bromine, or another hot tub shock, the minerals in the water start to oxidize or rust.

The consequence is a murky, discolored hot tub water that commonly appears green or yellow.

High bromine/chlorine levels can cause more than just water discoloration.

It can also cause:

  • Irritation of the skin, eyes, and respiratory system.
  • It can cause itchy red skin and red eyes. 
  • It has a negative impact on the lungs. 

Bromine and chlorine are strong chemical molecules that corrode surfaces. Pillows, acrylic surfaces, filters, and other exposed surfaces are examples of surfaces that can be damaged quickly. 

Therefore keeping bromine/chlorine levels in check helps extend the life of hot tub equipments.

As a result, the optimal chlorine range is 1-3 ppm. 

Info: People who are more sensitive to bromine/chlorine may experience an almost implacable reaction to higher levels of bromine/chlorine. 

Why does the hot tub water turn yellow after shock?

The hot tub shock is not enough to magically clear the water as often promised.

In the worst case, the water in the hot tub turns yellow after using a hot tub shock.

But why is that so?

Unfortunately, a chemical interaction between dissolved minerals in the water – such as iron and copper, which are often found together due to their presence in groundwater sources – and the use of a hot tub shock might cause this.

After the shock, the consequence is a cloudy, discolored hot tub water that commonly appears green or yellow.

The solution: You have to brush your hot tub and start the filter before using the hot tub shock.

How to prevent yellow water in a hot tub?

The old adage goes that prevention is better than cure, and with that in mind, we recommend the following to keep algae out of your hot tub:

  • Make sure you cover your hot tub when it’s not in use to avoid pollen and dust and any risk of damage from natural elements like rain or snowfall.
  • You should replace your filters on a regular basis to avoid the buildup of dirt and bacteria, which can lead to illness.
  • Depending on the type of sanitizer you use, keep sanitizer levels in the proper range.
  • Shock your hot tub at once a week to kill any bacteria or contaminants that may have built up during the week. If you own an Ozonator, you could shock your hot tub with ozone instead of using a traditional chemical shock treatment.
  • Maintain alkalinity of 80 to 120 parts per million (parts per million).
  • You should drain your hot tub and clean it about once a month or as needed.

Following my suggested guidelines should prevent you from shocking your hot tub too often, thus avoiding the water’s pesky yellow coloration.

If you need to shock your hot tub, read my helpful guide in my other blog post.

Conclusion on yellow hot tub water

The presence of iron bacteria, organic waste, an overabundance of sanitizers, and a variety of other factors, as we’ve discussed, can turn the water in the hot tub yellow.

On the other hand, water discoloration does not always imply that the water is hazardous.

However, any changes in your water, whether in color or odor, should be investigated and resolved as soon as possible.

Purchase a test kit to test the water for various contaminants; otherwise, keep track of the amount of sanitizers distributed to the water.

In summary, clear yellow hot tub water usually indicates a high bromine residual and a low pH.

This is a common problem with bromine in hot tub systems because bromine can discolor some particles in the tub. The yellow color should disappear once the pH and total alkalinity have been properly corrected.

Do you have any further questions how to fix yellow water in your hot tub?

Contact me at @contactswimfool on Twitter, Facebook, YouTube, or Pinterest – I’ll be happy to help.

Have fun in your clean hot tub!

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Hi. I'm Max Berg. I've been in the pool industry since 2015 and have always felt drawn to water. I'm the author behind swimfool.com, where I share my years of experience in pool maintenance and give helpful tips on keeping a swimming pool or hot tub clean. My tips reduce the costs of water treatment and protect the environment.

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