Which hot tub chemicals do you need?

hot tub chemicals - chlorine-granules

Hot tubs need chemicals to keep the water safe and pleasant to be in, and to avoid damage to hot tub components.

It’s important to use the right hot tub chemicals to keep your hot tub working correctly. To know how much of each chemical to add, you’ll need to test your water.

Testing your hot tub water

Use Hotspring test strips to test for bromine, chlorine, alkalinity, pH and total hardness.

hot tub chemicals - test strips

For the first month of hot tub ownership, you will probably need to test your water every day to get it to the right levels. You’ll then need to test at least once a week, or every time you use it.


The two most common choices are chlorine or bromine. Both do the same job, it’s down to budget and personal preference which you choose. Chlorine is more cost-effective but some people are irritated by chlorine so may prefer to use bromine.


Chlorine reading should be between 3 – 5 ppm.

Use chlorine granules or chlorine tablets with a dispenser to reach the recommended reading.

Hot Tub Chemicals Chlorine


Bromine reading should be between 3 – 5 ppm.

Use bromine tablets with a bromine dispenser or brominator to reach the recommended reading.

Hot Tub Chemicals Bromine

Calcium Hardness (CH)

CH reading should be between 50 – 150 ppm.

CH is the amount of dissolved calcium in the water. Low levels can make the water corrosive and high levels cause scale formation on hot tub components.

If the CH level is too high, lower it with calcium remover. Once in balance, the CH reading normally remains stable until new water is added.

Total Alkalinity (TA)

TA reading should be between 40 – 120 ppm.

TA is a measure of the water’s ability to resist changes of pH. A low TA allows the pH to fluctuate easily. Use either Total Alkalinity increaser or pH Reducer depending on your reading.

Hot Tub Chemicals - Total Alkalinity


pH reading should be between 7.2 – 7.8.

The pH is the measure of the acidity and alkalinity of the water.

If the pH is too high:

  • Sanitiser isn’t effective
  • Water can become cloudy
  • Scaling is more likely

If the pH is too low:

  • Skin irritation can occur
  • Components can corrode

Use pH reducer to lower the pH level, or pH increaser to increase the pH level.

Hot Tub Chemicals PH

Filter cleaner

Use filter cleaner weekly to remove oils, minerals and debris from your filters. This helps keep your hot tub filters in tip-top condition and extends the filter’s life.

Hot Tub Flush

Use Hot Tub Flush just before draining your hot tub. It helps remove soap and oil from your hot tub plumbing system.

Non Chlorine Shock

Non Chlorine Shock is designed to be used once a week in addition to chlorine, plus after heavy or extended bathing.

Silver Ions

Your Silver Ions filter should be replaced around every four months. It helps keep the water clean, reducing the amount of sanitisers you need to add.

Looking for a more natural solution?

The ACE Salt Water System is a lower maintenance alternative for hot tub water care. Using patented diamond electrode technology, ACE uses less chemicals and automatically keeps your hot tub water fresher for longer, saving you time and money.

Still not sure what hot tub chemicals you need?

Get in touch today for help choosing the right products for your hot tub.