Chemicals & 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)


  • Cost-effective
  • 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


  •  Costly
  • Hard to find
  • Can deteriorate parts of hot tub, including rubber gaskets and certain plastics

Minerals (Nature2 or Frog)


  • Cost-effective
  • 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.