Calcium Hardness – The Solubility Controller

Calcium Hardness – The Solubility Controller

So far, we have discussed both pH, Total Alkalinity and how the two interact. This leads us on to our next subject – Calcium Hardness and it’s part in Water Balance. 

All water has an intrinsic hardness to it. This refers to the amount of minerals, such as calcium and magnesium, which can be found dissolved into it. Here in the UK, you can find all levels of hardness from very soft through to very hard. Check with your utility supplier to find out the level of water hardness you have in your area and be aware that it can vary from postcode to postcode. 

The water we use on a regular basis requires some level of hardness. Very soft water is highly corrosive – much like water with a low pH – and very hard water can cause aggressive limescale. 

If we look at very soft water or water with a low hardness, we are presented with a range of challenges. Symptoms of these different hardness levels are shown below:

Low Hardness water symptoms:

  • Deterioration of your spa’s metal components
  • Unwanted foam 

High Hardness water symptoms: 

  • Scale formation on surfaces
  • Cloudy water

For optimal performance, your spa or hot tub should have a calcium hardness reading between 100 – 250ppm (parts per million) for an acrylic finish. For plaster finishes, you are looking for a reading between 250 – 450ppm. Adding chemicals to adjust the pH can have drastic effects on your water hardness level. High pH water normally has a high hardness reading. 

You should endeavour to check the hardness of your water on a weekly basis. After checking, be prepared to use selected products to help adjust the water to suit your needs. For a water hardness that is too high, our Spa Scale Away can be used to remove excess minerals and keep your spa from developing scale. For a water hardness that is too low, our Calcium Hardness Increaser will help to raise its readings to the appropriate level. 

If you have any further questions regarding Calcium Hardness and Water Balancing, contact us today. Our friendly and experienced team are happy to answer any questions that you may have.

For our commercial and trade contacts, please contact us for a personalised quote. 



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