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These are the most important factors in achieving good water quality. As an absolute minimum, you should aim to:
Many of the demonstration pools you see at pool centres do no more by way of day to day maintenance than that. Most pool water disorders occur when there is no chlorine in the water, or when the pH has strayed.
For best results, however, it is strongly recommended that you should also keep a watch on:
and for pools using stabilised chlorine donors:
A detailed program for pool maintenance is suggested in the next section
Test daily (or more often in hot,sunny weather when the pool is in heavy use). The free chlorine reading using the DPD no 1 test tablet should be between 1.0 - 2.5ppm (or up to 4 - 5ppm for pools using stabilised chlorines like dichlor and trichlor).
Dose rate
Once a fortnight, superchlorinate, preferably with an unstabilised chlorine such as calcium hypochlorite or calcium hypochlorite to raise the free chlorine to 6-10ppm. Calculate the dose rate from the figures in the preceding section.
Test daily (or more often in hot,sunny weather when the pool is in heavy use). The pH reading using the phenol red test tablet should be between 7.2 and 7.6 (or as near the mid-point - 7.4 as possible).
Dose rate
Test once a month. The alkalinity reading using the Alkalinity M tablet count test should be between 100-200ppm for pools using stabilised chlorines; 80-120ppm for calcium hypochlorite or 120-150ppm for sodium hypochlorite.
Dose rate
Test two or three times a season. The calcium hardness reading using the tablet count test should be above 350ppm - the top limit is not too important.
Dose rate
Test once a fortnight. The cyanuric acid (stabiliser) reading using the turbidity/disappearing dot test should be a minimum of 30ppm to prevent decomposition of chlorine to sunlight in outdoor pools. The maximum level is a matter of debate - most professionals take the view that the performance of the chlorine is adversely affected if cyanuric acid goes above 160ppm. Dept of the Environment guidelines are for a ceiling of 200ppm. Best to aim for the lower figure - 160ppm.
Dose rate
In general, the longer the pool water is being filtered, the better it cleans the water. As a minimum, run the circulation pump continuously when bathers are in the pool, and for four hours out of twelve at all other times.
The purpose of the filter is to trap suspended particles in the sand or other media and stop them getting back into the pool. It is essential that the efficiency of the filter is not impaired. Follow the manufacturer's instructions and backwash it (i.e. reverse the flow and drain the dirt that has accumulated on the top of the media to waste). This should be done at least once a fortnight, but watch the pressure guage and do it more often if necessary. Sand should need renewal every 7 to 10 years. Check that flow through the pump strainer is not impeded by rubbish as part of the backwash routine.
Clean the skimmers once a week taking out leaves and anything else that could obstruct the water flow.
If you are not operating an automatic pool sweep, vacuum the pool once a week to remove solids that are not floating in suspension. Some (aluminium-based) water clarifiers will drop accumulated solids to the bottom of the pool, and vacuuming may be required shortly after treatment - see the instructions on the pack. Exclude air from the vacuum hose before connecting it to the attachment in the skimmer.
Brush the sides and bottom of the pool frequently, ensuring that any algae that may be discolouring the tiles, grouting or liner is removed (look for this around the steps, under-water lights and 'dead spots' where water movement is minimal). Brush towards the drain so that debris and dirt is drawn into the hopper and onto the filter.
Clean dirt from the water line with a chlorine compatible tile and liner cleaner if it appears. Greasy deposits can act as breeding sites for algae.
NEVER MIX DIFFERENT TYPES OF CHLORINE TOGETHER BEFORE DOSING, AND DO NOT ALLOW THEM TO MEET IN A CONCENTRATED FORM. IF SUPERCHLORINATING VIA THE SKIMMER, ENSURE THAT ANY CHLORINE TABLETS ARE REMOVED FROM IT FIRST.PRELIMINARIES
To convert to cubic metres, divide the answer by 220. Jot the figure down and keep it in a safe place. It is the foundation stone for sound pool management.BASIC GUIDELINES
A man I knew who had run a pool centre for many years used to send his customers away with a note on the back of an envelope telling them what to do to keep their swimming pool water in good condition for the season. He had written down two figures - the daily dose of chlorine required for the size of pool concerned, and what to do if the pH strayed outside the normal parameters.
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