Instructions for pool filling for the initial time

If a pool has been drained in order to affect a repair or it is the first fill of the season, in all cases it will be found that the quality of the water used for refilling is very poor. In a number of cases it will be found to be dark red in colour with a considerable amount of turbidity. If this water is to be clarified by normal method of filtration it may take several days as the filters build up back pressure so quickly that they may need backwashing several times in one day.

The quicker method to clarify the water is to flocculate with alum in the pool itself as follows:

1. Build up the reserve alkalinity in the water as it is filling by adding either 2.5 lbs. of soda ash or 5 lbs. sodium bicarbonate for every 10,000 gallons.

2. Add alum at the rate of 5 lbs. for every 10,000 gallons by dissolving in water and distributing over the surface of the water in the pool, followed by running the pumps for ten minutes or until the alum has dispersed and starts flocculating.

3. Stop the pumps and allow the floc to develop and settle overnight. Next morning, suck off the deposit which settles on the bottom by means of the vacuum sweeper.

4. Follow by the normal filtration treatment and chlorination and the water should be ready for use by the end of the day.

The Biological Quality of Pool Water

The majority of micro-organisms found in pool waters are not dangerous. In purifying the water no attempt is made to destroy all micro organisms which consist of bacteria, viruses, algae and fungi, but to reach a point where the destruction of all harmful bacteria has been achieved.

Secretions from the mouth, nose, skin and urination are the main sources of organisms such as bacteria and viruses which can be disease producing.

When routine bacterial tests are carried out on water, no attempt is made to identify specific disease producing micro organism

The bacteriological examination to determine the microbiological quality of pool water is based on the total colony count and presence of coliform organisms (or Escherichia coli).

The presence of bacteria detected by these tests does not mean that they are all dangerous, but it acts s a warning to indicate that harmful bacteria could also be present.

It is generally accepted that pool water, free from coliform organisms, is regarded as having a satisfactory bactericidal purity. It is generally agreed also, that this condition can be reached if the pool practices continual filtration and the maintenance of a free residual chlorine level.

However, to make sure that the treatment and chlorine level is adequate, samples should be taken under the worst peak load conditions and submitted to the Department of Health or bacteriological examination at regular interval.

Total Colony Count - This indicates the degree of general contamination of the water from all sources. It is usually found that the total colony count rises in proportional relationship to the bathing load. Pools practicing free residual chlorination are indicated by very low counts. A total colony count of less than 200 colonies/ml should be the objective.

Coliform Bacteria
The presence of Escherichia coli which is found exclusively in excreta of warm blooded animals, is a reliable indicator of fecal contamination of water.

Recommended Bacterial Limits
The New South Wales Department of Health has recommended the following limits for closed circuit public pools with continuous purification treatment:

1. 75% of samples covering any period of time from any pool shall not have a total colony count exceeding 50 colonies per 100 mls. and the remainder should not exceed 200 colonies per ml.
2. The arithmetic mean coliform density of all standard samples examined per month shall not exceed 1 per 100 ml. Coliform counts per standard sample shall not exceed 4 per 100 mlbs. in two consecutive samples.

When coliform counts in a single sample exceed the above limits, confirmatory samples are required and shall be examined daily until results obtained from at least two consecutive samples show the water to be of satisfactory quality.