Water Balancing in Spas & Hot Tubs

HOT TUB WATER BALANCING

What is Water Balancing?

Water balancing is the process of maintaining the correct chemical composition of your spa water. Maintaining correct water balance ensures that your chosen sanitizer works to maximum effect.

Correctly balanced water also feels and looks good and protects your spa shell and equipment.

Certain sanitising products, in particular Aquafinesse and Eco One, reduce the need to constantly monitor the balance of your water, but you should still test your water at regular intervals and be aware of the basics.

There are three steps to water balancing, all three are not always required:

Step 1 - Adjust the Total Alkalinity (TA)

Step 2 - Adjust the pH

Step 3 - Adjust the Calcium Hardness

Step 1 - Adjust the Total Alkalinity (TA)

Sanitiser	Recommended TA range
Active Oxygen	80 - 160 ppm (mg/litre)
Aquafinesse	30 - 160 ppm (mg/litre)
Chlorine / Bromine	125 - 150 ppm (mg/litre)
PristineBlue	30 - 90 ppm (mg/litre)

Total Alkalinity is simply a measure of all the alkaline minerals (carbonates, bicarbonates and hydroxides)  in your water.

 It is pointless worrying about your pH or Calcium Harness level until you have got the Total Alkalinity to within the correct range, so  always start here. 

You should maintain Total Alkalinity levels within the ranges shown in the table.

more about Total Alkalinity

 

Symptoms of Incorrect Total Alkalinity (TA)...

Step 2 - Adjust the pH

Sanitiser	Recommended pH Range
Active Oxygen	7.0 - 7.4
Aquafinesse	7.0 - 7.8
Chlorine	7.2 - 7.6
Bromine	7.2 - 7.6
PristineBlue	7.0 - 7.4

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. A number of factors can affect the pH level of your spa water, including the amount of sanitizer present, dilution with fresh water, introduction of air, chemicals and algae.

You should aim to maintain pH levels within the ranges shown in the table. [NB. You must ensure that your TA is within the recommended range for your chosen sanitiser before you adjust your pH.]

More about pH

 

Symptoms of Incorrect pH...

Step 3 - Adjust the Hardness

Sanitiser	Recommended Total Hardness Range
Active Oxygen	100 - 500 ppm (mg/litre)
Aquafinesse	100 - 500 ppm (mg/litre)
Chlorine / Bromine	100 - 500 ppm (mg/litre)
PristineBlue	less than 250 ppm (mg/litre) - measured as Calcium Hardness

Water hardness is the concentration of the calcium, magnesium, carbonates and other mineral salts in your water.  The only slightly complicated thing here is to understand the difference between Total Hardness and Calcium Hardness.

Most test strips test for the Total Hardness of your water, that is the concentration of all dissolved mineral salts.  The Calcium Hardness is the element of the Total Hardness attributable directly to Calcium Carbonate.

Pristine Blue Users Beware: If you use PristineBlue at a sanitiser it is the Calcium Hardness, not the Total Hardness, that you must measure because the calcium ions bind to the copper ions and reduce the capability of the sanitiser to work properly. To test for Calcium Hardness you should use a calcium hardness test kit, not test strips.  The PristineBlue system includes a product called PristineCheck ro reduce the Calcium Hardness of the water.

What ever sanitizer you use, the Total Hardness should be ideally tested on first filling your spa and thereafter at monthly intervals. As water evaporates from the spa the minerals get left behind and become more and more concentrated, consequently the hardness of the water in your tub will increase over time.  The recommended range for all sanitisers other than PristineBlue is 100 - 500 ppm (mg/litre).  It is very unlikely that your water will rise above that range, but if it does topping up the spa with tap water at a lower hardness will reduce the level.

If the Total Hardness in your tub is too low (very soft water), etching can begin to occur on the tub surfaces which, over time,  will become abrasive and uncomfortable for bathers.  Apart from the discomfort, rough surfaces are not good because they also increase the likelihood of problems with algae growth and make cleaning more difficult.

More about Hardness

 

Symptoms of Incorrect Hardness...