Hot Tub Water Chemistry

How to guide for hot tub chemicals and spa care.


With a few simple steps and know-how you'll learn here, you'll be on your way to a pleasant and healthy hot tubing experience for yourself, your family and friends. If you are new to the wonderful world of hot tubs, start here!


Hot Tub Start up Steps and Water Balancing


Start Up Procedure

  • After you washed out and cleaned your hot tub shell and filter, reinstall the hot tub filter.
  • Fill the hot tub with fresh water tap water, make sure it's not water running through a water softener.
  • If you live in an area where the water is hard, use the Pure Fill Pre Filter when filling the spa. Do not fill the hot tub with soft water
  • Start the hot tub and let in heat up. Once the hot tub water is at or near operating temperature (95-104 deg), test water to get total Alkalinity, pH and Calcium Hardness reading
  • Adjust the Alkalinity to be between 80-150 ppm (120 ppm is ideal)
  • If Alkalinity is low, add Alkalinity booster. If Alkalinity is too high, you can lower this by using pH Down
  • Adjust the pH to be between 7.2 and 7.6
  • If pH is low, add pH Up to raise pH level
  • If pH is high, add pH Down to lower level
  • Ideal Calcium Hardness level for hot tub is between 100-200 ppm.  If your Calcium Hardness is below 100, use Calcium Increaser to raise it
  • If your water contains high levels of Calcium, add Stain Scale Control to protect against staining, scaling and cloudy water
  • Once your water is in balance, you can adjust the chlorine/Bromine levels.


If Using Bromine

  • Bromine Tablets
  • add 1.5 oz (50g) of Granular per 250 gal (1000 litres).
  • Add 4 oz (120 g) of Spa Shock per 250 gal (1000 litres).
  • This will establish an immediate bromine residual for disinfection.
  • Fill your floating feeder with bromine tablets and adjust the bromine level to 3-5 ppm
  • Maintain a 3-5 ppm Bromine residual.
  • Keep an eye on your pH level as Bromine tablets tent to bring it down over a period of a week.


If Using Chlorine

  • Granular hot tub Chlorine
  • Add 4 oz (120 g) of Spa Shock per 250 gal (1000 litres)
  • Add 1/2 oz (15 g) of Granular hot tub chlorine per 250 gal (1000 litres).
  • Test for Chlorine after 15 minutes of circulation.
  • If Chlorine level is below 3-5 ppm, add another 1/2 oz (15 g) of granular hot tub chlorine per 250 gal (1000 litres).
  • Maintain a 3-5 ppm chlorine residual.


Spa Tabs

  • Add 4 oz (120 g) of Spa Shock per 250 gal (1000 litres)
  • Fill your floating dispenser with Chlorine tablets
  • Maintain a 3-5 ppm chlorine residual.
  • Test weekly for Chlorine.  Adjust floating dispenser accordingly.
  • Keep an eye on your pH level as Bromine tablets tent to bring it down over a period of a week


Daily Maintenance (prior to use)

  • Use the AquaChek Test Strips to test for chlorine/bromine levels to see if they fall between 3-5 ppm and dose according to the attached instructions on the product container
  • Test Hot tub pH levels to see if they fall between 7.2 and 7.8. If not within these parameters use Hot Tub pH Up or pH Down according to instructions
  • If water is foaming use our Defoamer Product


Weekly Maintenance

  • Shock Hot tub with none chlorine based Spa Shock.
  • Clean Filter using Filter Cartridge Cleaner or rinse thoroughly. It's a good idea to have a spare, clean filter on hand to swap with the dirty one


Periodical Maintenance (Every 2 months or so)

  • If you live in an area with hard water (high Calcium) add Stain & Scale Control 
  • Clean hot tub and cover with a Cover Cleaner or a week solution of chlorine (3-5mg/litre)
  • Change water (might only be needed every 3 or 4 months). Follow the "Draining your Hot Tub" steps bellow.


Draining your Hot Tub

Every 3 months or so, it is necessary to change the water in your hot tub. Over time the water absorbs minerals, chemicals and other soluble materials. Sanitizers also begin to lose their efficiency as a result of the higher workload placed on them. The Total Dissolved Solids (TDS) level increases and the water will start to look dull and lifeless.

Some hot tubs are equipped with a drain valve that one can attached a hose to. This is usually located inside your hot tub's access panel. If your hot tub does not come equipped with a drain valve, you must siphon the water out. Here are some methods you can use:

  • Visit your local Hot Tub supply store and purchase a hot tub siphon called the "Quick Drain".
  • connect a hose to a tap and submerge the other end in the hot tub water. Turn the tap on until the hose is full of water. Then turn off the water and disconnect the hose at the tap. Run the hose down an incline to allow the water to continue siphoning.
  • use a Submersible Pump
  • Generally a small amount of water will still remain in the tub after using either of these methods. It's a good idea to have a Wet/Dry Vac (Shop Vac) on hand to get all the water out.


As a general guide us the following formula to determine how often the spa should be drained:

  • Size of Hot Tub (gallons) ÷ 3 ÷ daily bathers = days between draining and refilling.

Don't live by this formula. If you hot tub water looks dirty, smells or is excessively foamy, we recommend that you change the water


Cleaning your Spa/Hot Tub


Surface Cleaning


Over time, Scum lines, scale lines, and mineral deposits can build at the waterline on your spas surface. This provides an ideal breeding ground for bacteria and algae. We recommend you clean you hot tub every 2 or 3 weeks. To remove these lines easily and prevent them appearing follow these steps bellow.

  • Drain 4 to 6 inches of water out of your tub to expose the water line
  • Apply our EcoOne Spa Shell Cleaner to a sponge or cloth.
  • Using the sponge, wipe down waterline around the entire tub
  • Take a clean wet cloth or sponge once again wipe down the water line around the tub
  • Repeat this process to the entire spa surface every-time you change the spa water (every 2 to 3 months)


Cover Cleaning

Your hot tub cover can take a real beating, especially if it is outside in direct sunlight. Follow these instructions to clean, protect and to put the life back into your vinyl cover. Again, we recommend you clean you hot tub cover every 2 or 3 weeks.

  • Apply our Clean & Perfect Cleaner to a wet sponge or cloth.
  • Wipe down the exterior of the cover. If heavy soiled area, apply higher concentration of cover cleaner to that area.
  • Rinse with clean water

Water Chemistry Explained


What is Water Balancing?

  • Water balancing refers to maintaining the correct chemical composition of your Hot Tub/Spa water. Maintaining correct water balance is crucial to your enjoyment, health and longevity of your hot tub.


Calcium Hardness

  • It is important to achieve the correct level of calcium in your water, the levels of which will vary depending on where you live and where your water supply comes from. Soft water tends to be low in calcium and hard water tends to be higher. Every time you top up or refill your hot tub with fresh water you need to check levels of calcium.
  • The ideal calcium hardness level for a hot tub is between 100 -200mg/If the level in your hot tub is below this it could lead to corrosion damage. If you do find the level is low, then use Calcium Hardness Increaser to bring it up to the correct level. If the level in your hot tub is above this it can lead to the water appearing cloudy. As a result, calcium can be deposited on the tub shell, heater element, filter cartridge element and the pipe work within. To reduce this use Spa Essentials Stain & Scale which controls Stain & Scale to correct the level.



  • This also depends on your water source and should be checked every time fresh water is added. The ideal Total Alkalinity for your hot tub is between 100 - 150 ppm. If your test strip shows between this it will prevent the pH of the water fluctuating. If the level falls below the recommend amount the water can become corrosive causing damage to the hot tub equipment. This being the case, we suggest using Alkalinity Increaser to raise levels.
  • If the level is too high, the water can become poor in clarity and scale will form.


pH Levels

  • pH is a measure of the acidity or alkalinity of your water. The pH scale has a range of 0 - 14, with 7.0 being neutral. Water with a pH below 7.0 is acidic and above 7.0 is alkaline.
  • It is essential you regularly check the pH of your hot tub water using 4-Way Test Strips. The ideal pH range is between 7.4 and 7.8 ppm. If the pH level is below 7.4 use Spa Essentials pH Up to raise the level and if the pH level is above 7.8 use pH Down to drop the level.
  • Maintaining proper pH levels provides the most comfortable condition for hot tub users and has a good sanitizing efficiency
  • pH levels below 7.0 can damage the hot tubs jets, the cover and head cushions and the pump seals, if below 6.0 damage can occur in weeks rather then months or years.



  • Sanitizing your hot tubs water is vital to kill bacteria and prevent algae growth. Levels should be checked regularly using Test Strips. You can use either Chlorine or Bromine to adjust the levels.



  • Bromine is an effective sanitizer and ideally suited to hot tubs.
  • Produces less of a chemical odor than Chlorine Tabs
  • Effective over a wide pH range
  • Available in slow dissolving Tablet form or Granular.
  • Bromine level should be between 3 - 5 ppm



  • Most commonly available in granule form for hot tubs.
  • Disinfects immediately
  • Chlorine level should be 3 ppm
  • The least harshest of all hot tub water sanitizers due to it being virtually pH neutral, meaning it won't continually drag the pH down like Bromine Tabs and Chlorine Tabs do.



  • We recommend that you shock your hot tub on a weekly basis using Non Chlorine Spa Shock. This destroys odours and other undesirable additions such as perspiration, cosmetics and body oils. By doing this weekly it improves the comfort and hygiene for hot tubs users.