Pool Types

There are two types of pool, domestic and commercial, where domestic pools are constructed for individual usage and the commercial ones being pools installed for public use like the case of schools, hotels or even municipal installations. These can further be classified as “free board”, “deck level” or “horizon” based on the circulation system.

“Freeboard” is the standard pool type with the water level 50 mm to 100 mm below the top of the wall tiles and a surface skimmer to remove leaves and other floating debris.

“Deck level” level pools have a peripheral overflow channel and a balance tank. When the pump I running, water is taken from the balance tank and pumped into the pool until it overflows into the channel and then back to the balance tank.

  “Horizon” pools are a variation on the deck level concept but without the peripheral channel The top of the pool wall where the water will overflow is built 50 mm lower than the rest to create the “horizon” effect.

Pool Water Level

Maintenance of the correct pool level is most important to ensure proper operation of the skimmers in a freeboard pool or the peripheral drains in a deck level pool.

Freeboard Pools

The correct level for freeboard pool is approximately half way up the skimmer mouth or about 100 mm (4ins) below surround level. The level can be raised to improve the aesthetics of the pool. The level of the pool will drop when the filter is backwashed or rinsed and as a result of evaporation. Periodic refilling will therefore be necessary and this is normally done with a hosepipe connected to a stamp pipe.

Deck level and Horizon Pools

The correct level for deck level and horizon pools is the top of the wall but for these pools it is the amount of water in the balance tank that is critical for correct operation. The pool is considered to be full when, with the circulation pump off, the water in the pool is at the top of the pool walls and the level of the water in the balance tank is 600 mm (2ft) below the top of the balance tank. The water level in the balance tank should be checked periodically and replenished as necessary. It is important to note that over-filling the balance tank can result in water overflowing from the tank and under-filling will affect the efficiency of the peripheral drainage system. However, if there is a shortage of water and the level in the balance tank is too low for the overflow to operate, the valve from the balance tank should be closed and the pool operated as a freeboard pool using the main drain only.

Trouble Shooting

Well cared for pool water will last indefinitely. Water lost through evaporation can be replenished from the mains or when it rains with very little effect on the overall chemical balance. However heavy rain can add substantial amounts of water in the pool and this can lead to a rapid growth of algae. It is therefore essential that the chlorine level and pH be tested after heavy rain and the water treated accordingly.

Pool Water is Green

Green pool water is caused by a build up of algae. This condition can be cured by, first checking the pH, adjusting if necessary and then shock treating with chlorine. The pump and filter should then be left on for at least twenty-four hours to disperse the chlorine uniformly throughout the pool. If the water is still green at the end of this period, check the residual chlorine level using the colour coded comparator in the standard test kit and if necessary repeat the dosage.

Pool Water Cloudiness

Pool water cloudiness is more often than not caused by high (and sometimes low) pH. Adjusting the pH to between 7.2 and 7.6 will usually cure this problem though it may be necessary to run the filtration system for 24 hours to get clear water again. It should be noted that if the pH is either too high or too low then the effectiveness of the chlorine will be reduced and if the water is also green then shock treatment with chlorine will be necessary once the pH is within the correct range.

Coloured Water

Coloured water (reddish brown or brownish black) usually indicated the presence of iron or manganese. This can occur if steel circulation pipes start rusting and also if certain types of borehole water are used to top up the pool. In either case the solution is to flocculate, shock treat the water with chlorine and then to either remove sediment with a vacuum or by letting the filtration system operate continuously for 24 hours. It should be noted that if there is a significant amount of sediment to be removed then the filter will have to be back washed more frequently than normal to avoid clogging.

Pump Failure

There will be times when the pool pump will break down and in these circumstances it will not be possible to circulate or filter the pool water for some days. In this situation continue to treat the pool water with double the normal daily chlorine dosage whilst monitoring and adjusting the pH as necessary. This will ensure that the water remains sanitized and although there may be an accumulation of dirt the water will remain in an acceptable condition for short periods. It should be noted that, even if the water gets very dirty, once the pump is operating again, the filter system will be able to clean it and it is unusual to have to empty and refill the pool with fresh water.

Faulty Filter

If the filter becomes defective it can be by-passed by turning the MPV to "RE-CIRCULATE". Chemical dosage should be doubled and the pH should be monitored as normal. When the pump is operating the chemicals will be dispersed uniformly but there will of course be a build up of dirt over time. This can be easily removed once the filter has been repaired.