Basic Pool Care for Privately Owned Swimming Pools

<BODY BGCOLOR="ffffaa" TEXT="0000ff" LINK="000aaa" ALINK="ff0000" VLINK="c000c0"> <A NAME=top></A> <CENTER><H1>Basic Pool Care</H1> <H3>Guidelines on running a privately owned swimming pool for those using chlorine sanitisers</H3></CENTER><P> <STRONG>For an explanation of techical terms, follow the links or see <A HREF="tech.htm">A Layman's Guide to Technical Terms</A> or <A HREF="ph.htm">pH Explained</A>.<P> <OL><EM><A HREF="#para1"><LI>Preliminaries</A> <A HREF="#para2"><LI>Basic Pool Care</A> <A HREF="#para3"><LI>Recommended Maintenance Program - Swimming Pool Chemicals</A> <A HREF="#para4"><LI>Recommended Maintenance Program - Swimming Pool Hardware</A></LI></OL></EM><P> <HR><P> <A NAME=para1></A> <OL><LI><H3>PRELIMINARIES</H3><P> <UL><LI>Buy a good chemical test kit<P> <LI>Calculate the volume of water in your pool using the formulae<P> <UL><LI>For rectangular pools - Length x Width x Ave depth (in feet) x 6.25 = volume in gallons <LI>For round or oval pools - Length x Width x Ave depth (in feet) x 4.9 = volume in gallons<P></UL> 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.</UL><P> <HR><P> <A NAME=para2></A> <P><LI><H3>BASIC GUIDELINES</H3> 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 <A HREF="tech.htm#cl2">chlorine</A> required for the size of pool concerned, and what to do if the <A HREF="tech.htm#ph1">pH</A> strayed outside the normal parameters.<P> These are the most important factors in achieving good water quality. As an absolute minimum, you should aim to:<P><P> <P> <OL><H3><LI>MAINTAIN FREE CHLORINE LEVELS</H3>Make sure <A HREF="tech.htm#hocl">free chlorine</A> never falls below 1.0<A HREF="tech.htm#ppm">ppm</A>. This is to kill harmful germs and algae.<P> <P> <H3><LI>SHOCK DOSE</H3> <A HREF="tech.htm#supercl">Superchlorinate</A> the pool once a fortnight to bring the free chlorine up to 6-10ppm, using a <A HREF="tech.htm#shock">shock chlorine</A>. This will break down <A HREF="tech.htm#comcl">chloramines</A> and organic pollution.<P> <P> <H3><LI>CHECK THE pH</H3>Correct the <A HREF="tech.htm#ph1">pH</A> if it falls below 7.2 or rises above 7.6. Correct pH will ensure the chlorine is working effectively.</OL><P> <P> 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:<P> <UL><LI><A HREF="tech.htm#wbal">Water balance</A>; the most important features of which are:<P> <UL><LI>pH - as above<P> <LI><A HREF="tech.htm#talk">Total Alkalinity</A>. Low alkalinity can make it difficult to maintain the pH. High alkalinity can lead to cloudy water or scale on the surfaces.<P> <LI><A HREF="tech.htm#calh">Calcium Hardness</A> Correct calcium hardness will help protect pool surfaces.</UL><P>and for pools using stabilised chlorine donors:<P> <LI><A HREF="tech.htm#clstab">Cyanuric Acid</A> (stabiliser). You need enough stabiliser to prevent waste of chlorine to sunlight, but not so much that it impairs the effectiveness of the chlorine.</UL><P> A detailed program for pool maintenance is suggested in the next section<P><HR></STRONG><P> <A NAME=para3></A> <STRONG><LI>RECOMMENDED MAINTENANCE PROGRAM - CHEMICALS<P> <UL><LI>Free Chlorine<P> Test daily (or more often in hot,sunny weather when the pool is in heavy use). The <A HREF="tech.htm#hocl">free chlorine</A> reading using the DPD no 1 test tablet should be between 1.0 - 2.5<A HREF="tech.htm#ppm">ppm</A> (or up to 4 - 5ppm for pools using stabilised chlorines like <A HREF="tech.htm#dichl">dichlor</A> and <A HREF="tech.htm#trichl">trichlor</A>).<P> <EM>Dose rate</EM> <UL><LI>For dichlor - 125g per 15,000 gallons to raise free chlorine by 1ppm<BR> <LI>For trichlor - recharge the skimmer or feeder device with tablets and control chlorine levels by adjusting the water flow<BR> <LI>For <A HREF="tech.htm#caocl2">calcium hypochlorite</A> - 100g per 15,000 gallons to raise the free chlorine by 1ppm<BR> <LI>For sodium hypochlorite - 0.4 of a litre per 15,000 gallons to raise the free chlorine by 1 ppm</UL></UL><P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <UL><LI>Superchlorinate<P> 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.<P> WARNING: </STRONG><EM>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.</EM><STRONG></UL><P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <UL><LI><A HREF="tech.htm#ph1">pH</A><P> 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).<P> <EM>Dose rate</EM> <UL><LI>To raise pH - 0.7kg of soda ash (sodium carbonate) per 15,000 gallons per day until the correct reading is obtained.<BR> <LI>To lower pH - 0.7kg of dry acid (sodium bisulphate) per 15,000 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.</UL></UL><P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <UL><LI><A HREF="tech.htm#talk">Total Alkalinity</A><P> Test once a month. The alkalinity reading using the Alkalinity M tablet count test should be between 100-200ppm for pools using <A HREF="tech.htm#stabcl">stabilised chlorines</A>; 80-120ppm for calcium hypochlorite or 120-150ppm for sodium hypochlorite.<P> <EM>Dose rate</EM> <UL><LI>To raise the alkalinity - 2kg of sodium bicarbonate per 15,000 gallons per day until the correct reading is obtained.<BR> <LI>To lower the alkalinity - 1.4kg of dry acid (sodium bisulphate) per 15,000 gallons per day until the correct reading is obtained. Dose the dry acid in one spot in the pool - in this way it will affect alkalinity more than pH</UL></UL><P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <UL><LI><A HREF="tech.htm#calh">Calcium Hardness</A><P> 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.<P> <EM>Dose rate</EM> <UL><LI>To raise the calcium hardness, add calcium chloride flakes at the dose rate recommended on the pack. If it is difficult to keep calcium hardness above 350ppm, you should consider changing to calcium hypochlorite as your principal pool sanitiser</UL></UL><P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <UL><LI><A HREF="tech.htm#clstab">Cyanuric Acid</A><P> 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.<P> <EM>Dose rate</EM> <UL><LI>To raise the stabiliser level (which will usually only be necessary in pools on <A HREF="tech.htm#stabcl">unstabilised chlorines</A>) - 2kg of cyanuric acid per 15,000 gallons.<BR> <LI>To lower the stabiliser 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 <EM>pro rata</EM> e.g. to lower the stabiliser level from 180ppm to 160ppm, it will be necessary to replace just over 10% of the water.</UL></UL><P></STRONG> <HR><P> <A NAME=para4></A> <STRONG><LI>RECOMMENDED MAINTENANCE PROGRAM - POOL HARDWARE<P> <P><UL><LI>Cycle time<P> 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.<P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <LI>Filter<P> 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.<P>Check that flow through the pump strainer is not impeded by rubbish as part of the backwash routine.<P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <LI>Skimmers<P> Clean the skimmers once a week taking out leaves and anything else that could obstruct the water flow.<P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <LI>Vacuuming<P> 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.<P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <LI>Brushing<P> Brush the sides and bottom of the pool frequently, ensuring that any <A HREF="tech.htm#algae">algae</A> 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.<P> <HR SIZE="4" WIDTH="200" ALIGN="CENTER"><P> <LI>Tide Marks<P> 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.</UL></OL><P> <CENTER><FONT SIZE=1>&copy Copyright remains with the author. All rights reserved. See <A HREF="cright.htm">conditions of copyright</A></FONT></STRONG><P> <HR><FONT SIZE=2><STRONG><A HREF="#top">Back to top of page</A>/ <A HREF="pools.htm">Back to home page</A> <HR><P> Pool Owners Guide: </STRONG><A HREF="dosing.htm">[Dosing strategies]</A> <A HREF="trouble.htm">[Problem solving guide]</A> <A HREF="tips.htm">[Topical tips]</A><BR> <STRONG>Technical Section: </STRONG><A HREF="tech.htm">[Technical terms defined]</A> <A HREF="ph.htm">[pH explained]</A> <A HREF="water.htm">[Balanced water test]</A> <A HREF="bestbuys.htm">[Recommended products]</A><BR> <STRONG>Buy Your Own Pool: </STRONG><A HREF="why.htm">[The reasons people do]</A> <A HREF="newpool.htm">[The choices, the costs]</A> </FONT SIZE></CENTER> <HR> </BODY>