Chemicals and Chemistry: Know Your Hot Tub’s Needs

Chemicals and Chemistry: Know Your Hot Tub’s Needs

Purchasing a hot tub is a large investment – one that you want to enjoy as long as possible. Keeping your spa clean and sanitized is the best way to see that investment pay off for years to come.

Here’s our cheat sheet to hot tub chemistry and keeping yours clean and safe:

Sanitize, sanitize, sanitize

First off, you must decide which type of sanitizer you will use. There are five types: Chlorine, Salt System, Bromine, Soft Soak, and Minerals. Depending on preferences and needs, pick which sanitizer will work best for you.

Chlorine (granular)



Easy to manage and mix into your hot tub

Aggressive bacteria killer


Unpleasant smell due to oxidation of hot water

Stops working after killing bacteria

Bromine (granular or tablets)



More effective at killing types of algae

Continues working after attacking bacteria

Oxidation improves its lifespan

Works well in wide range of pH levels


Unstable—sun’s UV rays destroy bromine quickly, making it good for hot tubs not in direct sunlight

Soft Soak  


Liquid– making for easy application

Makes water appear sparkly

Smoother feel for swimmers

Less frequent application than chlorine and bromine

No odor when oxidized



Hard to find

Can deteriorate parts of hot tub, including rubber gaskets and certain plastics

Minerals (Nature2 or Frog)



Easy to manage

Fresh smell

Less chlorine


Must mix with chlorine

Slow and stale unless mixed


The Shock Treatment

In order to keep your hot tub’s chemistry balanced it should be shocked every once in a while. “Shocking” is the routine of applying a treatment to your water that oxidizes and breaks-down dead organic material left in your sanitizer system.

Periodic shocking is critical for clear, clean hot tub water. Some shock treatments even have the added benefit of pH buffers and water clarifiers. Depending on how often and how many people used the tub, you should shock regularly. Also, you should determine which shock treatment to use based on the type of your sanitizer.

Chlorine Hot Tubs

  • Add more chlorine
  • Use non-chlorine shock

Bromine Hot Tubs

  • Add more bromine
  • Use non-chlorine shock

Biguanide Hot Tubs

  • Use non-chlorine shock made specifically for the brand used

Mineral Hot Tubs

  • Use non-chlorine shock to keep chlorine levels low

Namaste: Control Your Water’s Balance

There are many chemicals you must balance to maintain your hot tub. When the mineral components of spa water are all correctly proportioned your water is balanced. In order to achieve this balance, you must check alkalinity, maintain a low pH level, and have the right amount of soft vs. hard water. Using test strips, you can test the measurements and adjust accordingly.

Alkalinity and pH

Total Alkalinity (TA) is a pH stabilizer that keeps your pH from drastically changing.

Both alkalinity and pH chemicals are inexpensive but extremely important. If the levels are too low it can cause damage, especially to your heater. If they are too high there will be a milky residue around water flows. That’s why it’s important to routinely check your hot tubs levels.

If both levels are low

Add alkalinity and both will increase

Afterwards, make sure to adjust the pH if it didn’t go to the correct level

If both are too high

Use pH decreaser to drop it down

Make sure to adjust your alkalinity to the correct level before the pH.

Soft vs. Hard Water and Calcium Hardness

Maintaining the correct balance of soft and hard water is critical to maintaining your spa. Having too soft of water can be corrosive to the shine of your tube and even lead to excessive foaming problems. Having too hard of water can lead to calcium hardness, which slowly eats away at the shell, pipes, and other parts of your tub.

If the water is too Hard

Use a calcium filter

Combine the water with calcium treatment chemicals

Control the calcium by using solutions that maintain spa minerals

If the water is too soft

Add calcium hardness increaser           

By maintaining the right chemistry for your spa, you’ll have your hot tub for years to come.

For more information, visit our spa page!

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