HomeGalleryVideo ImagesStep -Step concreteStep by step blockStep by step linerSpring PoolsMarbelite swimming poolsBrazilian Slate swimmingAutomatic CoverLandscapingPool RefurbishmentTelescopic CoversIndian StoneLiner ImagesConcrete ImagesChemicalsConstructionGuniteRefurbishment 2011 MaySwimming Pool Hot Showers

Water Balancing


pH control of your swimming pool

  • Balancing your pool-water is a vital part of keeping a healthy pool environment.
  • The disinfection system you choose will have complimentary products to control your pH.
  • A correct balance is achieved when the level of acidity and the level of alkalinity closely match the natural levels.
  • This relationship is known as the pH value and is measured on a scale from 0-14 with 7 being neutral.

    High pH value – Alkaline conditions

    • A high pH value (above 7) indicates a higher content of alkaline substances than acid types in the water.
    • If the pH value is too high, then the effectiveness of the disinfection process (when using chlorine) is reduced. Scale formation may occur, the water could become cloudy and the capability of the filter might be reduced due to blockage.

      Low pH value – Acid conditions

      • A low pH value (less than 7) indicates a greater acidic than alkaline content.
      • If the pH value is too low, it is probable that corrosion will occur around the pool fittings.
      • Most importantly a low PH may lead to skin and eye irritation.

      Ideal pH

      • As you can see, though your pool water may appear clean you can only be certain that it is safe and healthy if you regularly check (and if necessary re-adjust) the pH value.
      • The ideal pH value is 7.2 – 7.6.
      0 1 2 3 4 5 6
      7.2 to 7.6
      8 9 10 11 12 13 14

      Adjust pH as follows:

      Add to Water
      Below 7.2
      pH PLUS / ALKALI
      0.5kg/45m3(cubed) (10,000 gals)
      Below 7.6
      0.5kg/45m3(cubed) (10,000 gals)

      Test water after 24 hours, repeat as necessary until desired level is achieved.As suggested in the introduction, the water you use to fill your pool (tap water) surprisingly may not be ideal swimming pool water.Calcium hardness


      Water hardness


      Tap water varies greatly depending on where you live. For example, water in Scotland, where the ground is predominantly hard granite rock, is very ‘pure. Hard rock will not dissolve quickly on contact with rain water so the water remains relatively unaffected, just picking up minor mineral content, after it hits the ground. This soft water will generally have a low pH value (that is to say higher acidity) and will lead to corrosion if left untreated.

      In Kent, however, with its chalky white rock, rain water picks up ‘impurities’ such as calcium salts which will raise the alkalinity of the water. This hard water with its higher alkalinity content can cause cloudiness and limescale formation.

      Hardness is the measurement of the amount of calcium salts present in the water. It is nly expressed in milligrams per litre (mg/l) – the concentration of calcium in the water.

      Water hardness is also increased by water evaporation. When water evaporates any dissolved minerals (like calcium carbonate) will remain, increased in concentration (higher ppm, or mg/ltr). Calcium hardness is important because of what is known as water’s ‘hunger’ for calcium. If there is not enough calcium in the water a level below 200 mg/l (ppm) then the water will try to find calcium from the pools surroundings and fitting. This may cause corrosion problems.

      On the other hand, too much calcium in the water will lead to will lead to calcium deposits (scale formation). Your ideal calcium hardness level should be between 200 and 500 mg/l (ppm).

      Hardness - mg/l (ppm)
      Over 300
      Description of water
      Moderately soft
      Slightly hard
      Moderately hard
      Very hard

      Too soft
      1. Check TA and increase to 80 – 140 mg/l (ppm) if necessary. (See below).
      2. Add 0.7kg per 45³ (10,000 gallons) to increase hardness by approx. 10mg/l (ppm)

      Too hard

      1. Check TA and decrease to 80 – 140 mg/l (ppm) if necessary. (See below).
      2. If hardness persists – part empty pool and refill. Check calcium hardness on refilling the pool and if necessary repeat the process.


Total Alkalinity


Total Alkalinity is the measurement of the amount of alkali (in the form of carbonates, bicarbonates and hydroxides) present in your pool water.

It plays an important part in the control of your pool’s pH level.

If the Total Alkalinity is too low rapid changes of the pH level can result, causing corrosion and unsafe or unpleasant swimming conditions. High Total Alkalinity is not as great as a concern although it does make adjusting the pH level difficult. The most likely problems are cloudy water and limescale.

Total Alkalinity, like calcium hardness, can be easily measured with a pool testing kit. Ideally you should aim for a level between 80 and 140 mg/l (ppm).

New marbelite, concrete and tiled pools may produce a higher than average T.A. reading during their first two years due to a leaking of carbonates and bicarbonates from the materials used.

Remember that keeping Total Alkalinity at the right level, as well as protecting the swimmers, will ultimately prevent your pool from corroding or deteriorating, and make pH control easier.

Adjust Total Alkalinity as follows:

Add to Water
To increase TA
TA Plus / Bicarb
0.8 / 45m³
(10,000 gals)
Total amount required may be added to pool in one dose.

To decrease TA

TA Minus
1lt / 45m³
(10,000 gals)
to lower TA by approx.
6 mg/l (ppm)
Reduce in stages until correct TA is obtained.

Running your pool


Your pool should now be ready for swimming.

The next step is keeping your pool-water in great condition.


Disinfection (or sanitisation) is the process of removing harmful bacteria, and possible sources of infection from the water.
In other words it is the method you can use to guarantee your pool water is clean and safe. Even if the pool is not regularly in use and the water looks clear, if left untreated bacteria can easily build up and cause possible infection.

Here is a guide to the options you can take to maintain your pool water. The recommendations here are for outdoor and indoor pools. The water condition will change due to the level of usage, the amount of backwashing and topping up that you do and the weather.

Twice Weekly
Super Stabilised Chlorine Granules

Chlorine Tablets




Soft & Easy


Smart Sticks


The most commonly used chemical for disinfection is chlorine. Bromine, (the main brand is Aquabrome) is also widely used, in conjunction with a slow erosion feeder (Brominator). Chlorine free treatments are rapidly gaining in popularity. For example active oxygen has advantages for the pool user over traditional chlorine. It has a much gentler effect on the skin, minimising odours and offers a more environmentally friendly system.

Smart Sticks and other multifunctional products are designed to last longer than the traditional tablets and need checking weekly and replenished as necessary.

It is advised that whatever system you use the disinfection product is checked every week, and you record your results (see Swimming pool maintenance charts on pages 10 and 11). Each product shown here comes with a group of complimentary products as a part of a total water care system. Further information on all these products is freely available at your local Sunspot dealer.

Forms of Water Treatment

Chlorine granules
Chlorine tablets
Liquid chlorine (SODIUM HYPO)
Shock granules
Bromine tablets
Active oxygen
Physical form

Available ingredient

51% available chlorine
90% available chlorine
14-15% available chlorine
65% available chlorine
90% active ingredient
6 to 7
2 to 3
12 to 13
10 to 12
3 to 4
6 to 7
Direct application
Direct application
Dosage rate for shock treatment
90g per 50m³ (11,000 gallons) gives 1 mg/l (ppm) rise in chlorine
Use tablet feeder or skimmer 2×225g tablets per 50m³ (11,000 gallons)
75g per 50m³ (11,000 gallons) gives 1mg/l (ppm) rise in chlorine
Use bromine feeder
1 double sachet per 20m³ (4,400 gals weekly)
Recommended for shock treatment
Use Bayrol Bayro shock
Dosing rate
4ltr per 50m³ (11,000 gallons) will give 10mg/l (ppm) rise in chlorine
750g per 50m³ (11,000 gallons) will give 10mg/l (ppm) rise in chlorine



Excess chlorine

If you find that you have put too much chlorine into the pool, the addition of Sunspot Chlorine Reducer (Sodium Thiosulphate) in the recommended quantities, will get the levels back to normal. Sunspot Chlorine Reducer also works when bringing down high bromine levels.

Water clarity

From time to time pool-water can become cloudy. This is sometimes caused by particles too small to be removed by the filter (dust, dirt, etc).

The addition of a Super Water Clarifier, Granular Floc or Sparkle Tabs, will get your pool-water looking clean and clear again.

Flocculant tablets should never be added to skimmers when chlorine tablets are in use. Flocculant tablets should be put into the pump basket in this situation.

Scale and metal deposit prevention

Sometimes a build up of metal or scale impurities can lead to discolouration or cloudiness of your pool-water and surrounds.

Water colouring

Metals will cause the following colour changes:

Maganese - Brown/Black
Copper - Blue/Green or Dark Brown
Iron - Light Brown
Zinc - Off White

Using a sequestering agent such as Conquest or Stain & Scale inhibitor will remove these impurities.

Shock treatment/superchlorination

Shock treatment restores water clarity and removes any organic waste which can produce unpleasant smells or lead to eye and skin irritation.

This treatment is intended to complement your regular water treatment programme – be that a traditional sanitiser (chlorine or bromine) or the active oxygen method.

Algae control

Although adding chlorine regularly to your pool-water will kill bacteria and keep most algae growth at bay, occasionally some may still appear in the pool. This can be countered by using one of the algaecides in the range. Persistent algae growth will usually only be a problem if your pool is not being treated and tested regularly.

Filter cleaning

From time to time grease, scale and other contaminants will build up in the filter. Regular use of a filter cleaner will prevent the growth of harmful bacteria and generally keep the filter clean. The domestic pool should be backwashed weekly as part of your maintenance routine. Once backwashed the addition of a flocculant or water clarifier will give you sparkling water.

Tile band cleaning for liner pools

Cosmetics and body oils may form a dirty mark around the waterline area of your pool. A regular clean with a Waterline Cleaning Paste or  Tile and Liner Cleaner will keep the sides of your pool grease free.

Do not use household cleaning products as they can react with pool water disinfectants.

Pool surrounds

By keeping the area around your pool clean you will reduce the amount of dirt and harmful bacteria that is brought into the pool by it’s users; making it easier to keep the water clear and healthy. The use of a hard surface cleaner such as Sunspot Springclene is recommended.

Pool leakage

In all pools there will always be some loss of water through evaporation. However, if you find there is some leakage from the system (either from the liner, concrete or pipe work) there are easy to apply leak sealers you can use which are very effective and come with comprehensive instructions. It is worth bearing in mind, however, that these products are designed for minor leakages only. If problems with your pool persist contact your local dealer for advice.

Remember to read all chemical product labels and follow directions for use