Your top priority as a spa owner is to keep the water sanitized. For any sanitizer to work well, however, the water must be balanced. Balanced water is neither corrosive (acidic) nor scale forming (alkaline). Five factors affect water balance: pH, total alkalinity, calcium hardness, total dissolved solids and temperature. If any of these five factors is on the low side, metal corrosion and staining may result. If any are on the high side, you may see cloudy water, staining and mineral deposits. In either case, bathers are likely to experience eye and skin irritation.

A change in any one factor can affect the others, so your challenge is to “balance” the water using various types of chemicals that keep each factor in its proper range. The process may sound complicated, but it isn’t as difficult as you may think. It just requires a little study on your part so that you understand how each factor contributes to the overall water quality and how to adjust it if it’s out of whack.

Calcium Hardness
We are all familiar with hard water from the furring effect it has on a kettle element. A spa heater element will suffer the same consequences if the water is allowed to remain hard for prolonged periods. Cloudy water, scum lines and scale build up are also symptoms of high calcium hardness. The proper Calcium Hardness level in a spa is 100-200mg/l.
Due to high water temperatures, evaporation of spa water occurs, leaving the minerals in the spa water. Consequently, the Calcium Hardness of the water will tend to increase. However, the addition of soft water (most domestic supplies are soft) to top up the spa will reduce Calcium Hardness levels as will using a product such as Guardex Spa Stain & Scale Away.
Prolonged periods of low Calcium Hardness can lead to corrosion of the spa equipment and surfaces. Use Guardex Spa Higher Cal to raise the Calcium Hardness. This is often required when the spa water is changed.

Total Alkalinity
Total Alkalinity is the sum of all the alkaline substances in the water. Its ideal level is 125-150 ppm.
One of the miracles of a proper Total Alkalinity level is that it can help stabilize the pH. On the other hand, if Total Alkalinity is too low, pH will fluctuate drastically, making it a constant struggle to maintain perfect water balance. Use Guardex Total A to raise the level of Total Alkalinity and Guardex pH Reducer to lower the level (Note: this will also reduce the pH level).

pH
Water pH is a measure of acidity or alkalinity. The pH scale runs from 0 to 14 with 7 being neutral. Values lower than this are acidic and higher values are alkaline. The ideal pH level for a spa is between 7.2 and 7.6 with 7.4 being ideal. Not coincidentally, this is the same as the pH of the human eye!
A low pH means the water is acidic or corrosive. Over time this can etch metals and will cause bather discomfort. Low pH also causes chlorine sanitisers to dissipate quickly (one reason bromine is preferred).
A high pH means the water is alkaline or scale producing and will cloud water and form scale deposits on spa surfaces. As with low pH, high pH levels cause chlorine to become less effective and skin and eye irritation may occur.
Use Guardex pH Increaser to raise pH levels and Guardex pH Decreaser to lower the level.

Total Dissolved Solids
The term Total Dissolved Solids (TDS) refers to the concentration of conductive chemicals, bather waste and other solids that can accumulate in the water. You can not see these solids because they are dissolved in the water, but they can still cause corrosion. TDS should not be allowed to exceed 1500ppm above the start-up TDS level.
Electronic TDS meters and liquid test kits are used to establish TDS levels. A reputable spa dealer should offer assistance with this. The best way to reduce TDS is to introduce fresh water to the spa (as with high Calcium Hardness).

Q How do I test the water balance ?
A Test strips are the most convenient way of testing water balance. Insta-Test 5 will give levels for pH, total alkalinity and Calcium Hardness as well as sanitizer levels. Insta-Test 3 are a cost effective choice for daily use as they give levels for pH, Total Alkalinity and sanitizer (the factors most likely to vary). Establishing the level of Total Dissolved Solids requires a liquid test kit or electronic analyser.

Ozone
An ozonator produces and releases ozone which is an effective sanitizer. However, ozone doesn’t last long in water and there is no way of maintaining a measurable ozone residual in spa water. Therefore, ozone MUST be used in conjunction with a sanitizer.
Ozone is very effective at destroying bacteria and algae and also causes Total Disssolved Solids to be precipitated for easy removal by the spa filters.

Q Can Ozone be fitted to any spa ?
A A lot of spas come with factory fitted with ozone generators. Many models are supplied “ozone ready”. If you spa is able to accept an ozone unit, then installation should be a straight-forward operation.