How to raise or lower the pH in a spa

Figuring out how to raise or lower the pH in your spa is important, as it's one of the key parameters in maintaining balanced water. pH varies according to a number of factors, so it's important to measure it regularly and correct any imbalance. Read all about it in this article.

ICO SPA measures water pH with its connected sensor

What is the ideal pH level for a spa?

How to define water pH?

pH (or Hydrogen Potential) is one of the most important parameters to measure regularly when owning a spa, as it plays a key role in balancing the water.

Measuring the pH allows you to control the quality of your spa water on a scale from 0 to 14.

  • If the pH of the water is below 7, the water is acidic.
  • If the pH of the water is greater than 7, the water is said to be basic.

A neutral pH enables the disinfectant treatment (chlorine, salt, bromine) to work optimally to eliminate pollutants present in the water. This helps maintain safe, healthy water for bathers, reducing the risk of infection or illness.

illustration ideal scale of ph water spa values

Control water balance

Balanced water is defined by three parameters: pH, alkalinity (TAC) and water hardness (TH). The aim is to obtain balanced water, i.e. water that is healthy and comfortable (or pleasant) for the skin. Water Balance gives a synthetic value of water quality. How to maintain water balanced in your spa.

How to measure pH ?

Water pH should be measured at least during weekly spa maintenance, or daily depending on the number of bathers and frequency of spa use.

  • Chemical pH testers: disposable colorimetric strips that need to be immersed in water before reading the measured value.
  • Hot tub water analyzers: these measuring devices give more accurate and more frequent measurements than color strips. Connected pH sensors, such as ICO SPA, make monitoring your spa water even simpler by automatically measuring pH every hour for you.

To find out more about these measurement systems, you can read this comparison of pH testers.

How to correct a too-high or too-low pH?

It's important to be aware of the factors that cause variations in the pH level of your spa water, so that you can prevent variations accordingly. For example, one of these factors is the number of bathers, so you'll need to activate filtration first. You'll need to measure the pH after a few hours to correct it, if necessary.

Factors influencing pH variations: water temperature, bathers, filtration and chemical treatment.

How to lower pH?

Si le pH est supérieur à 7,5 (pour un spa traité au chlore) ou 7,8 (traitement au brome) il faut verser du produit pH moins dans l’eau de votre spa puis effectuer un cycle de filtration de l’eau. Reprendre une mesure pH après 6h.

Rebalancing the pH of water can take time, so it's best to add products little by little to rectify it (following the manufacturer's recommendations).

Raise pH if too low

Si le pH est inférieur à 7,2 : ajouter du produit pH plus en le dissolvant dans un seau d’eau (du spa) pour protéger son revêtement, puis versez le contenu dans l’eau de votre spa. Ensuite, vous devez activer la filtration pour un cycle complet. Mesurez à nouveau le pH après 6h.

pH remains unchanged after treatment

If the pH of the water does not change after the addition of pH - or +, this may mean that your water is over-buffered: it is the alkalinity level (TAC) that is too high and prevents the pH from regulating. The TAC should be between 100 and 200 mg/liter (depending on the treatment used in your spa).If you find yourself in this situation, you need to resolve the TAC problem to restore a balanced pH by activating a full filtration cycle. Sodium bisulfate can also be added. You should avoid swimming for 48 hours if you use this product.

The effects of too low or too high a pH 

Un pH déséquilibré compromet l’efficacité des produits désinfectants comme le chlore ou le brome. Cela peut également irriter la peau et les yeux des baigneurs, changer la couleur de l’eau, et générer le développement d’algues.

High pH can damage your spa's lining. This leads to cloudy water, limescale encrustations on the walls and, in extreme cases, the appearance of green algae (due to the loss of chlorine efficiency).

Too low a pH can lead to corrosion of your equipment, deterioration of pool walls, and irritation of bathers' eyes and skin.

Things to remember about spa pH

To conclude this article, remember that water pH is one of the most sensitive elements in maintaining balanced, healthy, clear water. Controlling pH should be part of your spa maintenance routine. To save time and regularly analyze your spa's water quality, opt for a connected probe to simplify your spa maintenance. Click on the image to discover ICO SPA.

image video youtube presentation ico spa, the connected water analyzer that measures pH, ORP and TDS