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Maintaining Total Alkalinity and pH

This post is one of a series of posts designed to help you maintain your hot tub water and ensure you have consistently crystal clear, clean hot tub water.

Now that you have selected the sanitiser (Bromine/Chlorine/Active Oxygen) best suited to your needs you need it to be efficient. For the sanitiser to be most effective the Total Alkalinity and pH need to be within the correct parameters.

What is pH?

pH is a measure of how acid or alkali your water is.  The scale runs from 1-14 with 7 being neutral in the middle.


When you have equal amounts of acid compounds to alkaline compounds they cancel one another out and your pH will be 7. Imagine marbles on the SeeSaw you could have one small marble on each side of the SeeSaw. Or, you could have one giant marble on each side but as long as the amounts are the same they will cancel one another out. This way you make the pH 7.

What is Total Alkalinity?

The total amount of alkaline compounds in the water. In other words everything from 7-14 on the SeeSaw scale above. The Total Alkalinity acts as a stabiliser for your pH. This means that we need to have a certain amount of Total Alkalinity in the water in order to make the pH easy to control. If the Total Alkalinity is too low then the pH will keep dropping low and if it is too high, the pH will keep rising. This is why it is recommended to get the Total Alkalinity of your hot tub water correct first before you adjust the pH.

What Happens if my pH is Too Low?

If your pH is consistently low for long periods of time this means the water is acidic. Acidic water is corrosive and so you may find rust forming on stainless steel, rubber seals perishing. You could develop a leak from a pump as the seal has perished.  In the very worst cases the water can damage the shell surface.

The water also isn’t very nice to bathe in if the pH is very low. You might find that your skin feels prickly or itchy and there may be a strong chemical type smell from the water when the jets are on.

What Happens if my pH is too High?

A high pH can cause scale formation. Signs of this can be calcium flakes forming in the water (they look a bit like fish food flakes but white). The internal sides of the spa might start to feel rough and you may visibly see white scale forming around the water line. Internally the scale will build up around the heater element and inside the pumps.

If you live in a hard water area it is particularly important to monitor your Total Alkalinity and pH. It is adviseable to maintain these at the lower end of the normal range and use and additional product such as AquaSparkle Scaleaway to help prevent the build up of scale.

The required Total Alkalinity and pH levels are as follows:

  • Total Alkalinity: 80 – 120ppm
  • pH: 7.2 – 7.6

The sanitiser is the most important thing for keeping bacteria at bay in your hot tub water. The sanitiser will work even if the Total Alkalinity and pH are not correct. However, to get the best out of your sanitiser and for it to be most effective you need the Total Alkalinity and pH to be within the correct parameters.

There are a few other things you need to keep a check on too to make sure your hot tub water is completely balanced. Check out our other blog posts to find out more:

  • Hot Tub Sanitisers
  • Shock Dosing Your Hot Tub Water
  • What To Do If your Hot Tub Water is Foamy or Cloudy

About Alfresco Life

Alfresco Life are an approved Sundance Spas hot tub outlet and have been supplying, installing and maintaining hot tubs for over 15yrs.

We are family owned and run business located in Cheshire. We differentiated our self as a hot tub outlet specialising in luxury outdoor living products. Over the years we have hand picked a selection of quality products that will be an asset to your home and garden.

We have the knowledge and experience to design and build you a luxurious haven right in the back of your garden.