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• Buy a good chemical test kit.
• Calculate the volume of water in your pool using the formula:
  • For rectangular pools - Length x Width x Ave depth (in feet) x 7.5 = volume in gallons
  • For round or oval pools - Length x Width x Ave depth (in feet) x 5.4 = volume in gallons

 

 

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BASIC GUIDELINES

A man I knew who had run a pool center 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.

These are the most important factors in achieving good water quality. As an absolute minimum, you should aim to:

MAINTAIN FREE CHLORINE LEVELS

 

Make sure free chlorine never falls below 1.0ppm. This is to kill harmful germs and algae. 

SHOCK DOSE

 

Superchorlinate the pool once a week to bring the free chlorine up to 6-10ppm, using a shock chlorine. This will break down chloramines and organic pollution.   You can superchlorinate once every 2 weeks during cooler weather.

CHECK THE pH

Correct the pH if it falls below 7.2 or rises above 7.6. Correct pH will ensure the chlorine is working effectively.

Many of the demonstration pools you see at pool stores 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 water balance; the most important features of which are:

• • pH.- 7.2 to 7.6

  • Total Alkalinity. 80 ppm to 120 ppm - Low alkalinity can make it difficult to maintain the pH. High alkalinity can lead to cloudy water or scale on the surfaces.

  • Calcium Hardness.200 ppm to 400 ppm - Correct calcium hardness will help protect pool surfaces.

  • Cyanuric Acid(stabilizer). 30 ppm to 50 ppm - You need enough stabilizer to prevent waste of chlorine to sunlight, but not so much that it impairs the effectiveness of the chlorine.

A detailed program for pool maintenance is suggested in the next section.

 

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RECOMMENDED MAINTENANCE PROGRAM - CHEMICALS

FREE CHLORINE 

• Test weekly (or more often in hot, sunny weather or when the pool is in heavy use). The free chlorine reading should be between 1.0 - 3.0 ppm 

Dose rate

• • For dichlor - 125g per 15,000 gallons to raise free chlorine by 1ppm
  • For trichlor - recharge the skimmer or feeder device with tablets and control chlorine levels by adjusting the water flow
  • For calcium hypochlorite- 1 lb. per 10,000 gallons 

  • For sodium hypochlorite - 1 gallon per 10,000 gallons 

     

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SUPERCHLORINATE

• Once a week, superchlorinate, preferably with an unstabilized 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.

WARNING:NEVER MIX DIFFERENT TYPES OF CHLORINE TOGETHER BEFORE DOSING, AND DO NOT ALLOW THEM TO MEET IN A CONCENTRATED FORM. .

 

 

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pH

• 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

• • To raise pH - 1/2 lb of soda ash (sodium carbonate) per 10,000 gallons per day until the correct reading is obtained.
  • To lower pH - 1/2 lb of dry acid (sodium bisulphate) per 10,000 gallons per day until the correct reading is obtained. Dose the dry acid by dispersing over as wide an area of the pool as possible.

 

 

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TOTAL ALKALINITY

• Test once a month. The alkalinity reading should be between 80-120ppm 

Dose rate

• • To raise the alkalinity - 2 lbs of sodium bicarbonate per 10,000 gallons every 4 hours until the correct reading is obtained.
  • To lower the alkalinity - 1/2 gallon muriatic acid per 10,000 gallons per day until the correct reading is obtained. Pour muriatic acid into a bucket of pool water and disperse around perimeter of pool.

 

 

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CALCIUM HARDNESS

• Test two or three times a season. The calcium hardness reading should be 200-400 ppm.

Dose rate

• • To raise the calcium hardness, add calcium chloride flakes at the dose rate recommended on the pack. 

 

 

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CYANURIC ACID

• Test once a week. The cyanuric acid (stabilizer) reading should be a minimum of 30ppm to prevent decomposition of chlorine to sunlight in outdoor pools. 

Dose rate

• • To raise the stabilizer level (which will usually only be necessary in pools on unstabilized chlorines) - 2lb of cyanuric acid per 10,000 gallons.
  • To lower the stabilizer level - there is no chemical additive to achieve this. You will need to replace part of the pool water with fresh. The volume of water to be replaced will be pro rata e.g. to lower the stabilizer level from 180ppm to 160ppm, it will be necessary to replace just over 10% of the water.

 

 

• Cycle time

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 eight hours a day at all other times.

 

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• Filter

  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 week, but watch the pressure guage and do it more often if necessary. Sand should need renewal every 7 to 10 years.  Paper filters should be rinsed once a week and replaced when necessary.

   

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• Skimmers

Clean the skimmers once a week taking out leaves and anything else that could obstruct the water flow.

 

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• Vacuuming

  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.

   

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• Brushing

  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 drain and into the filter.

   

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• Tide Marks

  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.

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