A good level of calcium hardness is from 250-350ppm.  Low levels lead to corrosion problems and high levels will cause scale formation.

This is an indicator test which looks at the presence of bacteria of faecal origin. If faecal coliforms are present, it indicates that there is a possibility that other bacteria associated with the gut such as Salmonella or Campylobacter may also be present.

Chlorine is used to provide disinfection of the pool water, FAC levels should be maintained at 1.0-3.ppm or parts per million (also reported as g/m3 or grams per cubic metre). Too little chlorine leads to bacterial growth and waterborne illness. Too much affects eyes, nose and skin and is unhealthy long-term. Chlorine that has been ‘used up’ disinfecting pools will form Combined Chlorine. 

Chlorine can be present in water as free available and as combined chlorine (where free chlorine reacts with ammonia to form chloramines).  Both forms can exist in the same water.  FAC can be determined alone or both can be determined together as total chlorine. Testing for Total Chlorine will give the level of FAC and Combined Chlorine together, and subtracting the FAC from this gives the Combined Chlorine reading. Results are reported in g/m3.  Samples requiring chlorine testing must be in a container filled to the top and brought in to the laboratory as soon as possible to minimise chlorine loss.

APHA Method 4500-Cl G (adapted)

Measurement of the pH determination is one of the most important and frequently used tests in water chemistry.  Practically every phase of water supply and wastewater treatment are pH dependent.  At a given temperature the intensity of the acidic or basic character of a solution is indicated by hydrogen ion activity and referred to as pH. On a scale of 1 – 14, pH 1 is considered strongly acidic and pH14 highly alkaline (or ‘base’).  pH 7 is described as neutral.

APHA method 4500-H+ B

This bacteria is associated with eye and ear infections when dunking the head in swimming pools and can cause a rash on the body. The main problem with staphylococcus aureus and pseudomonas aeruginosa is that they can be relatively resistant to chlorine, and they therefore account for a large percentage of swimming pool and spa associated illness.

This test looks for the total number of bacteria present in the water. This test does not look for specific types of bacteria, but gives a general idea of how well the chlorination system is working. If there are high counts of bacteria it may be indicative of a problem.

This bacteria can cause skin irritations especially in wounds, cuts or abrasions. It can also cause sickness if swallowed or ingested. It can be found in infected wounds or in the nasal cavity.

The alkalinity of water is its acid-neutralising capacity.  Measurements are useful in the interpretation and control of water and wastewater treatment processes, and in determining the suitability of water to be used in irrigation.  Results for Total alkalinity (using standard method APHA2320B) are reported in gCaCO3/m3.

Total dissolved solids is a measure of all of the dissolved solids in the pool water, from the water source, added chemicals and atmospheric dust.  The maximum acceptable level in swimming pools is 1500ppm.