If you click any of the hyperlinked technical terms (underlined and in dark blue) in this frame, you will find them explained in more detail in the frame below. Click 'back to menu' in the bottom frame when you have read the definition if you want to reinstate the menu. You can increase or reduce the height of either frame by dragging the arrow pointer on the frame divider; you can even make the bottom frame invisible by this means if you need more screen space to read this problem solving guide.
It can be difficult to make an accurate diagnosis for any particular problem with pool water. It is usually a case of considering several possibilities and selecting the most likely cause from other evidence, such as water tests. Browse through the various explanations for each symptom and see which you think is most likely to be responsible.
The problems are grouped together in the menu below. Click on the relevant category and scroll to find more details on your particular pool problem:
SYMPTOM: Cloudy/milky Water. There are four possible causes - your test kit will give you the best idea as to which is the most likely.
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SYMPTOM: Stinging eyes, sore throat and skin irritation. There are three possible causes - use your test kit to see which is the most probable.
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SYMPTOM: Blond or tinted hair turns green.
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Also, be your own guinea pig - use another pool sanitised with chlorine and see if you get the same reactions. If not, your problems are probably more to do with water treatment.
Bear in mind as well that chloramines are formed by the breakdown of nitrogenous compounds such as perspiration, cosmetics, mucous etc when hypochlorous acid (free chlorine) reacts with them. The chloramines are eventually broken down by more hypochlorous acid to form harmless substances such as nitrogen gas. All this usually takes place in the pool water. However, the breakdown reactions can take place on the surface of the skin if for instance you have been working-out and sweating before swimming or using cosmetic preparations. Remove these nitrogenous compounds from your skin by taking a shower and washing thoroughly before entering the pool. The chances are you will find the pool water much more comfortable.
If neither of these suggestions help, then the likelihood is that you are one of the minority who experience an allergic reaction to chlorine. An allergy is defined as a hypersensitiveness to some foreign substance, small doses of which produce a violent and disproportionate reaction in the sufferer. Chlorine is unlikely to have been the original or primary allergen, but those suffering from allergies can unfortunately find themselves sensitised by chlorine
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SYMPTOM: Chlorine has been added to the water, but there is no reading on the test kit.
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SYMPTOM: The chlorine level is difficult to maintain. There are three possible causes.
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SYMPTOM: Tendency for the pH to remain low (below 7.2).
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SYMPTOM: Tendency for the pH to be permanently high (above 7.6).
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SYMPTOM: pH values are erratic and fluctuate.
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SYMPTOM: pH is locked.
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SYMPTOM: Tendency for the alkalinity to be too low.
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SYMPTOM: Loss of grouting in mosaic/tiled pools, or sharp edges around tiles. There are two possible factors at work here:
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SYMPTOM: Pool surfaces feel rough and scaly.
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SYMPTOM: Pool surfaces feel slippery.
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SYMPTOM: Tide mark on pool wall at water line.
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SYMPTOM: Ineffective filtration in sand filters.
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SYMPTOM: Ineffective filtration in cartridge filters.
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WATER CLARITY PROBLEMS
Fine suspended particles floating in the water can lead to a milky white discolouration. This will probably be due to a precipitation of dissolved hardness salts as result of high pH or high total alkalinity, or both. (Precipitation is a process where dissolved minerals become transformed into very small solid particles).
To correct alkalinity, the dose should be doubled. It is important to add the acid a little at a time and pre-dissolved at a dilution no stronger than 8:1.
Build up of dirt and bather pollution due to insufficient chlorine or poor filtration
The effectiveness of the chlorine has been reduced in pools using stabilised chlorine donors because the water is over-stabilised i.e. the levels of stabiliser (cyanuric acid) are too high. This prolongs the time it takes to kill organisms (bugs) which can proliferate and lead to haziness in the water.
The filter is blocked or is ineffective
At some stage, chlorine levels have fallen, or chlorine has become ineffective, allowing algae to colonise the water.
Steel or ferrous metal fittings in the circulation system e.g. pipes are being corroded by low pH. A shock dose of chlorine will then oxidise the ferrous particles creating rust. This can often happen after re-opening a pool.
BATHER DISCOMFORT PROBLEMS
This could well be a pH problem - the water could be too acidic or too alkaline. The pH of the human eye is around 7.4-7.5 - anything higher or lower will irritate. The problem would be made worse if the pH is out to the extent that it changes the species of chlorine (see pH explained)
High combined chlorine. Chloramines are known to be an irritant. Note carefully the results you get on your DPD no3 test. Also, if you get an unpleasant chlorine smell, its odds on that the problem is due to high chloramines.
Some detergents used for cleaning pool sides and removing scum lines (tide-marks) are incompatible with chlorine. This can unfortunately include many products sold specifically for this application. The resulting reactions in the water can lead to eye and skin irritation. Similar reactions can occur if soaps or shampoos get into the water, for instance if bathers jump in to rinse off.
High levels of copper in the pool. This can arise either because of over-use of copper based algicides, or because the pH of the pool water has been allowed to drop to a point at which it starts to corrode the copper fittings in the heater.
The most important thing is to make sure that you really are suffering from a genuine allergy and not something else. The discomfort you feel could be due to other factors. For instance, it be due to the fact that the pH of the water is too low or too high. Alternatively it could be due to high levels of combined chlorine (chloramines) - chloramines are known to be irritants. Both these things are explained in more detail in 'Stinging eyes, sore throat and skin irritation' on this page). Test the water for pH and chloramines and correct as necessary.
PROBLEMS WITH CHLORINE LEVELS
The chlorine level in the pool is so high that it bleaches the colouring agent in the test tablet. To confirm the diagnosis, see if you can detect a smell of chlorine off the surface of the water, or repeat the DPD no 1 test with only a droplet of pool water in the test tube and watch closely to see if there is a red discolouration before the bleaching occurs.
In outdoor pools, the hypochlorous acid (free chlorine) is being decomposed by ultra violet from the sun's rays
High water temperature. The logic is simple. Bugs are more at home in warm water and breed more quickly. The greater number of bugs will create a higher chlorine demand.
As a rough rule of thumb to bear in mind if there is a heat wave, if the pool water temperature goes above 80 degrees farenheit, the chlorine demand will double for each increment of 10 degrees.
Because chlorine levels have not been high enough, there has been a build-up of pollutants, and therefore an increase in chlorine demand.
WATER BALANCE PROBLEMS
This is usually due either to low pH of mains water (especially in soft water areas) or to the use of acidic chlorine donors, such as trichlor
This is due to either (1) high pH of mains water (especially in hard water areas) or (2) to the use of alkaline chlorine donors such as calcium or sodium hypochlorite, or (3) to hardness salts being leached from new concrete or mosaic pools.
The reason will be that the total alkalinity will be too low to buffer the pH
The water is over buffered due to high alkalinity. This is a not uncommon problem in hard water areas where the mains feed water has a high total alkalinity.
The local feed water is low in bicarbonates so that whenever the pool is topped up from the mains, it dilutes the bicarbonates in the pool. This is a particular problem in soft water areas.
PROBLEMS WITH POOL SURFACES
In soft water areas, the grouting is being etched by the pool water. This is because there is insufficient calcium in the water. There is a tendency for water to form an equilibrium by searching for calcium - in this case from the grouting or plaster substrate.
High levels of sulphate in the water. You will need to get your pool centre to test for sulphates to confirm this diagnosis. The sulphate level shoul not exceed 350ppm.
High sulphates are caused by (a) high sulphates in the mains water (b) the frequent use of dry acid (sodium bisulphate) or (c) use of aluminium sulphate as a water clarifier.
The balance between pH, total alkalinity and calcium hardness is incorrect, and the water is technically 'scale forming'.
This is probably algae forming a colony on the pool surface due to insufficient chlorination at some stage, or to a 'dead spot' in the water circulation.
What you are seeing is a build up of greasy deposits such as cosmetics, sun cream or body fats.
FILTRATION PROBLEMS
Either (a) sand has escaped from the filter leaving insufficient filter media to take out suspended particles, or (b) the filter is blocked by accumulated debris or (c) the sand particles are coated in calcium.
Either the cartridge is in poor condition, allowing particles to pass through it or the demands on it from debris in the water are too great for it to cope.
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