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Crystal Clear +Bacteria Free Spa Water

Hot tubs and pools can provide an environment for bacteria to grow. These bacteria can make you sick with an infection or disease.

This includes the Legionella bacteria that cause Legionnaires’ Disease, which can be fatal. As well, Pseudomonas bacteria can cause a number of serious infections, such as severe skin rashes, eye and ear infections, and pneumonia. Other pathogens that are spread through feces or vomit can also be transmitted through hot tubs and pools.

Examples include Norovirus and Cryptosporidium. These can all be controlled by maintaining the disinfectant level and cleanliness of the water.

For more information, see HealthLinkBC File #87 Norovirus and HealthLinkBC File #48 Cryptosporidium Infection.

How To Clean Green Water Colour In Hot Tub/At-Home Spa

Having a green colour in your hot tub will make you and your guests want to leave the water right away.

No one wants to relax and soak in dirty water. But if you just owned your first at-home spa, we understand your frustrations and confusion.

You might be asking yourself, why it turned green, or what can you do to get rid of the unpleasant colour. Cleaning the hot tub will eliminate the problem, but what's important is preventing it from happening again.

WR104 Algae in Cattle Tub | 80 gallon galvanized steel tub w… | FlickrWhat Makes it Colour Green?

There are many reasons for turning the water green in your hot tub, such as algae, insufficient sanitiser, minerals like iron, copper, manganese, and more.



Low Sanitiser Level

If the level of chlorine or bromine is low, it results in poorly sanitised water, causing the water to turn green.

Sanitising the water using chlorine will kill all the bacterias, and prevent algae from proliferating rapidly.

Maintaining the correct level of sanitiser for the at-home spa is important since a time might come where you get so busy to clean the hot tub. It will prevent the discolouration of the water.

In addition, shocking your at-home spa once a week is also an effective way of keeping the water clear and clean.

How To Raise Low Sanitiser Levels

      1. Test the water for sanitiser level.

      2. Depending on which sanitiser you will be using, adjust to reach the recommended amount.

      3. Allow the water to circulate for one day.

      4. Retest and adjust if necessary.

      5. Test it weekly to maintain the proper water chemistry of the hot tub.

Oxidation Of Copper, Iron, Manganese And Other Metals

One of the most common causes of hot tubs turning into green is the oxidation of metals. Water coming from wells or the municipal system contains high levels of metals, such as copper, iron, and manganese.

How can you tell if it is caused by excessive metal content? If the Total Alkalinity and pH levels are in balance, the water will turn clear with a green tint, like a food coloring added to water.

How To Remove Excessive Metal Content

  1. Test the water's Total Alkalinity, pH level, and Calcium Hardness.

  2. Adjust them to normal levels.

  3. Add Fi-Clor Cartridge Cleaner 100g Sachet to the filter/skimmer area. ( a preventative step in removing clear green water from your hot tub.)

  4. Retest the water chemistry and sanitiser levels, adjust where necessary.

Low pH Level

A low pH level can also induce a green colour to the water in the at-home spa. It allows bacteria to build up, which results in discolouration of the water. 

If the pH level is too low, since the water is acidic, it can erode metal and plastic over time.

In relation to high metal content, low pH levels can cause the copper to dissolve from your tub water's heating element.

How To Adjust Low pH

  1. Test water for Total Alkalinity and pH level.

  2. Start by adjusting the Total Alkalinity. 

  3. If it is high or low, adjust it first to help in regulating the oH (Hydroxide) level. 

  4. Retest the water and adjust if necessary.

  5. Maintaining the water should be done weekly by testing it. 

  6. When the pH level is in balance, follow the directions on "How To Remove Excessive Metal Content"


  • Test the water's Total Alkalinity, pH level, and Calcium Hardness.

  • Adjust them to normal levels.

  • Add Fi-Clor Cartridge Cleaner 100g Sachet to the filter/skimmer area. ( a preventative step in removing clear green water from your hot tub.)

  • Retest the water chemistry and sanitiser levels, adjust where necessary.


Algae growth in your hot tub results in a slimy coating all over your tub. It can quickly spread if the cover of the at-home spa is removed or left off during the day.

But, you must take note that algae comes in many different colors, such as black or mustard. 

Did you notice a slippery feeling in your hot tub? 

If yes, it is probably because of algae. Make sure to wash your swimwear if you have soaked yourself in a tub full of algae because it can stick to your bathing suit and swimming trunks!

How to Remove Minor Algae Growth

  1. Fill the hot tub water with an initial treatment of ClearWater Algaecide 1L, which can eliminate visible algae growth.

  2. For preventing algae, you may follow directions on the bottle for clear instructions of use.

How to Remove Heavy Algae Growth

  1. PLUMBING – A system flush will prevent the algae from spreading, as they could be hiding inside the plumbing.

  2. SHELL – After the system is flush, you have to drain, and clean the inside of the tub with a non-foaming cleanser.

    WARNING: Do not use bleach, vinegar, or any household cleaners. Such products will damage your shell and can alter the water chemistry.

  3.    3 . FILTER – Do a thorough deep cleaning on your filter or you may also replace the filter cartridge, especially if it is already 1 year or older. 


  5. TEST - Test the water's Total Alkalinity and pH and adjust to normal levels if necessary.

  6. ALGAE PREVENTION – Use Blue Horizons Algae Controller 500ml for weekly preventative measures, follow the instructions on the bottle.


Green water on the at-home spa isn’t always caused by algae, which is an aquatic plant with a slimy feature, and attaches to the corner of the hot tub.

It can also be caused by high copper or other mineral levels, or low Ph level. (There is no need to drain the green water caused by imbalanced water levels.)

Always remember to test the chemistry level weekly to maintain the water's proper levels, also the cleaning and draining of the hot tub should be done every 3 to 4 months.


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