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.
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
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
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.