Chapter 14 Pool Maintenance PDF

14-1 CHAPTER 14 MAINTENANCE WORK ON AF AND ITS PLANT ROOM 1 Maintain Water Quality Phenol Red solution...

14-1 CHAPTER 14 MAINTENANCE WORK ON AF AND ITS PLANT ROOM 1 Maintain Water Quality Phenol Red solution OTO (Othotolidine, for testing pH level a chemical liquid for testing total chlorine) Vial for testing and colour comparison Figure 14-1: Left - A Typical Set of Test Kit (minimum), and Right - A Typical Higher Range Test Kit for Multi Testing Figure 14-2: DPD#1 Tablet Strip An AF must provide and maintain in good working condition a testing kit for daily measuring of the concentration of the disinfectant pH value of the water in the AF. A minimum kit consists of two dropper bottles containing testing liquids for chlorine- and alkali- level.  14-2 At least once a month, water in the AF is to be sampled and analysed by a Government laboratory or any other approved laboratory and the test results are to be submitted to the Commissioner. Of course, the results must comply with the parameters for the chemical and bacteriological quality of water shall be as set out in the Schedule. 1.1 Problems with Water Quality The common problems are listed below: Water Quality Problems Cloudy, milky water Green water Rusty water Bather discomfort, including sections on eye sting, chlorine allergy Chlorination problems Water balance problems, including sections on pH, alkalinity Filtration problems 1.1.1 Water Quality Problem Symptom: Cloudy and Milky Water, there are four possible causes. 1.1.1.1 First possible cause: Causes: Fine suspended particles floating in the water can lead to a milky white discolouration. This will probably be due to a precipitation of dissolved hardness salts as result of high pH or high total alkalinity, or both. (Precipitation is a process where dissolved minerals become transformed into very small solid particles). Remedy: Lower the pH or alkalinity using dry acid. To correct pH, add dry acid at a rate of 1kg per 100 cubic metres (22,000 gallons) per day until correct reading is obtained. To correct alkalinity, the dose should be doubled. It is important to add the acid a little at a time and pre-dissolved at a dilution no stronger than 8:1. 1.1.1.2 Second possible cause: Causes: Build up of dirt and bather pollution due to insufficient chlorine or poor filtration. Remedy: Backwash the filter, then super-chlorinate by adding an unstabilised chlorine such as sodium hypochlorite or calcium hypochlorite to raise the free chlorine to 10ppm. Add a clarifier to ‘polish’ the water. 1.1.1.3 Third possible cause: Causes: The effectiveness of the chlorine has been reduced in AF using stabilised chlorine donors because the water is over-stabilised i.e. the level of stabiliser (cyanuric acid) is too high. This prolongs the time it  14-3 takes to kill organisms which can proliferate and lead to haziness in the water. Remedy: Replace some of the AF water by draining to waste (or carrying out an extra large backwash), then top up with fresh mains water. This will lower the level of the stabiliser. Super-chlorinate to 10ppm using the products recommended above. 1.1.1.4 Fourth possible cause: Causes: The filter is blocked or is ineffective. Remedy: Check the sand and replace it if necessary. Sand particles can become coated with calcium in some circumstances, especially in hard water areas. If the filter is not blocked and seems all in order in all other respects, treat with a filter cleanser to sharpen the sand. 1.1.2 Water Quality Problem Symptom: Cloudy and Green Water Causes: At some stage, chlorine levels have fallen, or chlorine has become ineffective, allowing algae to colonise the water. Remedy: Shock dose with an unstabilised chlorine such as calcium hypochlorite or sodium hypochlorite, or use an algaecide. Shock dosing usually produces the fastest results. For greenish discolourations (where the water is no more than tinted green), super-chlorinate to 10ppm. For more serious problems, where the water is pea-soup green and the bottom is invisible, shock dose up to around 25ppm. This will kill the algae. Brush off any algae that may remain on AF surfaces. Look for colonies behind step ladders and around underwater lighting. Backwash the filter 24 hours later to remove dead algae from the top of the filter media. Any remaining haziness in the water should be removed by using a water clarifier. The cationic clarifiers are best in this situation. Thereafter maintain chlorine at around 3ppm to prevent a recurrence. If the AF is particularly susceptible to algae, consider regular use of an algaecide or chlorine with added algaecide. 1.1.3 Water Quality Problem Symptom: Rust Red Water Causes: Probably, steel or ferrous metal fittings in the circulation system e.g. pipes are being corroded by low pH. A shock dose of chlorine will then oxidise the ferrous particles creating rust. This can often happen after re-opening an AF.  14-4 Remedy: It is necessary to act very quickly to prevent consequential damage such as staining of the liner, if fitted. Contact the AF installer to see if it is safe to drain down and replace the water all in one go, or whether this should be done by progressive dilution. Remove any rust staining from the AF surfaces with a good tile and liner cleaner. Replace the ferrous metal fittings using PVC or copper. Ensure the fresh water is properly balanced i.e. that pH and total alkalinity are within recommended parameters. 1.1.4 Bather Discomfort Symptom: Stinging eyes, sore throat and skin irritation. There are three possible causes - test kit would be useful to determine the most probable. 1.1.4.1 First possible cause: Causes: This could be a pH problem - the water could be too acidic or too alkaline. The pH of the human eye is around 7.4 to 7.5 - anything higher or lower will irritate. Remedy: Correct the pH - to lower the pH, add dry acid at a rate of 1kg per 100 cubic metres (22,000 gallons) per day until correct reading is obtained. And dose at the same rate with soda ash will raise pH. 1.1.4.2 Second possible cause: Causes: High combined chlorine - chloramines are known to be an irritant. Note carefully the results of DPD no 3 test. Also, if an unpleasant chlorine smell is present, its odds on that the problem is due to high chloramines. Remedy: Break the chloramines down by super-chlorinating the AF with up to 10ppm free chlorine. Aim to allow no more than one third of the total chlorine to be in the form of combined chlorine. 1.1.4.3 Third possible cause: Causes: Some of the detergents used for cleaning AF sides and removing scum lines (tide-marks) are incompatible with chlorine. This can unfortunately include many products sold specifically for this application. The resulting reactions in the water can lead to eye and skin irritation. Similar reactions can occur if soaps or shampoos get into the water, for instance if bathers jump in to rinse off. Remedy: Super-chlorinate to react-out the detergents. Change to cleaners that are chlorine compatible or abandon their use and resort to hard scrubbing with a brush.  14-5 1.1.5 Bather Discomfort Symptom: Blond or tinted hair turns green. Causes: Probably, there is a high level of copper in the AF. This can arise either because of over-use of copper based algaecides, or because the pH of the AF water has been allowed to drop to a point at which it starts to corrode the copper fittings in the heater. Remedy: Correct the pH - to raise the pH, add soda ash at a rate of 1kg per 100 cubic metres (22,000 gallons) per day until correct reading is obtained. A pharmacist should be able to recommend a shampoo to remove the unwanted pigment. 1.1.6 Bather Discomfort Symptom: Allergy to chlorine. Causes: Possibly, the most important thing is to make sure that a bather is really suffering from a genuine allergy and not something else. The discomfort felt could be due to other factors. For instance, it could be due to the fact that the pH of the water is too low or too high. Alternatively it could be due to high levels of combined chlorine (chloramines) - chloramines are known to be irritants. Both these things are explained in 'Stinging eyes, sore throat and skin irritation' (above). The water should be tested for pH and chloramines and corrected as necessary. Also, be your own guinea pig - use another AF sanitised with chlorine and see if there is the same reactions. If not, the problems are probably more to do with water treatment. Bear in mind as well that chloramines are formed by the breakdown of nitrogenous compounds such as perspiration, cosmetics, mucous etc when hypochlorous acid (free chlorine) reacts with them. The chloramines are eventually broken down by more hypochlorous acid to form harmless substances such as nitrogen gas. All this usually takes place in the AF water. However, the breakdown reactions can take place on the surface of the skin if for instance the bather has been working-out and sweating before swimming or using cosmetic preparations. Remove these nitrogenous compounds from the skin by taking a shower and washing thoroughly before entering the AF. The chances are that he will find the AF water much more comfortable. If neither of these suggestions helps, then the likelihood is that the bather is one of the minority who experiences an allergic reaction to chlorine. An allergy is defined as a hyper-sensitiveness to some foreign substance, small doses of which produce a violent and disproportionate reaction in the sufferer. Chlorine is unlikely to have been the original or primary allergen, but those suffering from allergies can unfortunately find themselves sensitised by chlorine. Remedy: If a bather thinks he has a genuine allergy, then sadly the only remedy is to change to a non-chlorine sanitiser. Be warned that a number of AF require to be dosed or shock dosed with chlorine. Consult an AF dealer for suitable alternatives.  14-6 1.1.7 Chlorination Problem Symptom: The chlorine level is difficult to maintain. There are three possible causes. Causes: Probably, the chlorine level in the AF is so high that it bleaches the colouring agent in the test tablet. To confirm the diagnosis, see if a smell of chlorine can be detected off the surface of the water, or repeat the DPD no 1 test with only a droplet of AF water in the test tube and watch closely to see if there is a red discolouration before the bleaching occurs. Remedy: Determine the approximate level of chlorine by diluting the sample of AF water with an equal quantity of natural or distilled water; multiply the answer by 2. If there is still no reading, repeat the process and multiply the answer by 4...and so on. If the actual chlorine reading is not too high (i.e. around 10ppm), suspend dosing and allow it to drop over a period of time. If the chlorine reading is significantly higher, or if there is a need to use the AF in the near future, add sodium thiosulphate to reduce the free chlorine. WARNING: The recommended dose rate is 0.5kg per 100 cu metres (22,000 galls). Apply this in several much smaller additions, testing after each dose. An overdose of thiosulphate can leave the AF water with 'negative chlorine' i.e. a chlorine deficit for a considerable time. 1.1.8 Chlorination Problem Symptom: Chlorine has been added to the water, but there is no reading on the test kit. 1.1.8.1 First possible cause: Causes: In outdoor AF, the hypochlorous acid (free chlorine) is being decomposed by ultra violet from the sun's rays. Remedy: For AF using liquid chlorine (sodium hypochlorite) or calcium hypochlorite, add stabiliser (cyanuric acid) at a rate of 3kg per 100 cu metres (22,000 galls). This should be dosed directly into the AF, NOT pre-mixed with the chlorine. Alternatively, switch to a stabilised chlorine - dichlor granules or trichlor tablets. 1.1.8.2 Second possible cause: Causes: High water temperature - the logic is simple. Bugs are more at home in warm water and breed more quickly. The greater number of bugs will create a higher chlorine demand. As a rough rule of thumb to bear in mind if there is a heat wave, if the AF water temperature goes above 27oC (80 degrees farenheit), the chlorine demand will double for each increment of 5oC (10 degrees farenheit). Remedy: The dose rate of chlorine must be increased proportionately. Keep a close check on chlorine levels in hot weather.  14-7 1.1.8.3 Third possible cause: Causes: Because chlorine levels have not been high enough, there has been a build-up of pollutants, and therefore an increase in chlorine demand. Remedy: Super-chlorinate the AF to around 10ppm free chlorine. 1.1.9 Water Balance Problem Symptom: Tendency for the pH to remain low (below 7.2). Causes: Likely, this is due either to low pH of mains water (especially in soft water areas) or to the use of acidic chlorine donors, such as trichlor. Remedy: Correct the pH - to raise the pH, add soda ash at a rate of 1kg per 100 cubic metres (22,000 gallons) per day until correct reading is obtained. Consider changing to a high pH chlorine source to help achieve a natural balance between the low pH of the water and the high pH of the chlorine donor. Dichlor is roughly pH neutral; calcium hypochlorite and sodium hypochlorite are high pH chlorine donors. 1.1.10 Water Balance Problem Symptom: Tendency for the pH to be permanently high (above 7.6). Causes: Likely, this is due to either: a. High pH of mains water (especially in hard water areas) or b. The use of alkaline chlorine donors such as calcium or sodium hypochlorite, or c. Hardness salts leaching from new concrete or tiled AF. Remedy: The remedy is the same irrespective of which factor is at work - correct the pH. To lower the pH, add dry acid at a rate of 1kg per 100 cubic metres (22,000 gallons) per day until correct reading is obtained. For (a) and (b), consider changing to a low pH chlorine source to help achieve a natural balance between the high pH of the water and the low pH of the chlorine donor. Trichlor is the obvious chlorine donor to choose. For (c), the difficulties with new concrete AF will clear up of their own accord given sufficient time. 1.1.11 Water Balance Problem Symptom: pH values are erratic and fluctuate. Causes: Likely, the reason will be that the total alkalinity is too low to buffer the pH. Remedy: Add sodium bicarbonate to ensure the total alkalinity remains above 100ppm. The dose rate is 3kg per 100 cu metres (22,000 galls) of AF water.  14-8 1.1.12 Water Balance Problem Symptom: pH is locked. Causes: Likely, the water is over buffered due to high alkalinity. This is a not uncommon problem in hard water areas where the mains-fed-water has a high total alkalinity. Remedy: Add dry acid to lower the total alkalinity to below 200ppm. The dose rate is 2kg per 100 cu metres (22,000 galls) of AF water. It is important to add the acid a little at a time and pre-dissolved at a dilution no stronger than 8:1. 1.1.13 Water Balance Problem Symptom: Tendency for the alkalinity to be too low. Causes: Likely, the local-fed-water is low in bicarbonates so that whenever the AF is topped up from the mains, it dilutes the bicarbonates in the AF. This is a particular problem in soft water areas. Remedy: Add sodium bicarbonate to raise the total alkalinity to around 100ppm. The dose rate is 3kg per 100 cu metres (22,000 galls) of AF water (this should raise the level by 20ppm per dose). 1.1.14 Filtration Problem Symptom: Ineffective filtration in sand filters. Causes: Either: a. Sand has escaped from the filter leaving insufficient filter media to take out suspended particles, or b. The filter is blocked by accumulated debris or c. The sand particles are coated in calcium. Remedy: For (a), it is simply a matter of topping up the sand. If (b), the filter is blocked by debris, backwash. If the problem is persistent, and the sand particles are becoming coated with calcium (more likely in a hard water area), use a filter cleanser. Figure 14-3: AF Cleaning Tools – Vacuum Head (left), Rake (centre) and Stainless Steel Bristle Algae Brush (right)  14-9 AF water test kit Strainer basket Test Leaf skimmer vial Wall brush Vacuum cleaner Another vacuum cleaner head head Figure 14-4: Other AF Maintenance Tools and Fittings 2 Maintenance of AF Surroundings Most people forget that most algae which grow in the AF come from the pathways and garden around the AF. Greenery should be cut back from the AF edge and from paths. This will reduce the growth of algae which can harbour bacteria. The algae also causes slippery surface on the paths and the floors around the AF. If necessary, brush across any slippery areas using a mixture of one part chlorine (1litre of liquid chlorine) to 10 parts (10 litres) water. Leave for 10 minutes to allow the solution to work and then flush off with large amounts of water. Protective clothes must be worn while carrying out such work. To avoid contamination, the areas surrounding the AF should be kept litter free. Food and drinks should not be allowed in the area. Imagine the vermin, birds and pets that could be attracted to the leftover and spilled food and drinks.  14-13 3 Maintenance of the AF 3.1 AF Wall Over time, deposits of mineral and organic matter would build-up on the walls of AF. These must be removed regularly to stop the chance of algae, bacteria or virus growing in the AF.  14-14 Brush the sides and bottom of the AF frequently, ensuring that any algae that discoloured the tiles and grouting are removed. Such areas would be 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. If tide line (water line) appears, the dirt must be cleaned from the water line with a chlorine compatible tile cleaner. The area where the water level sits is a common spot for the deposit of minerals, oils and lotions. All of these can harbour algae and bacteria and look dirty. 3.2 Damaged AF Tiles Obviously, the whole area would be wet one way or another, therefore tiles used for an AF, including the AF surroundings, AF steps, AF decks, changing rooms, foot- baths and common or public areas such as cafeteria, entrances, exits, should be non- slip type. In the AF, if tiles have come off, it is usually very difficult to replace them. Most manufacturers do not maintain an inventory of tiles of old styles and designs. It is best to find a reputable ceramic tile retailer and purchase tiles that closely resemble the existing tile in the AF. In addition, the appropriate tile cementing material and grout should be purchased with the tiles. Follow the instructions from the tile manufacturer to install the tile, which may also involve submerged work. Figure 14-5: Tiling work on AF floor 3.3 Loss of Grouting in Tiled AF, or sharp edges around tiles. There are two possible factors at work here. 3.3.1 First possible cause: The first possible cause is: In soft water areas, the grouting is being etched by the AF water due to insufficient calcium in the water. There is a tendency for water to form an equilibrium by searching for calcium - in this case from the grouting or plaster substrate. To remedy, re-grout the AF and increase calcium levels in the water by adding calcium chloride flakes so as to achieve a minimum calcium hardness level of 250ppm. Alternatively, use calcium hypochlorite for shock dosing or for regular sanitisation - calcium will be automatically added to the water in using this sanitiser.  14-15 3.3.2 Second possible cause: The second possible cause is: High levels of sulphate in the water. There will be a need to get the AF tested for sulphates to confirm this diagnosis. The sulphate level should not exceed 350ppm. High sulphates are caused by: a. high sulphates in the mains water b. the frequent use of dry acid (sodium bisulphate) or c. use of aluminium sulphate as a water clarifier. To remedy, there is not much that can be done if the cause is (a). If the suspected factor is (b) or (c), dilute with fresh water and switch to alternative methods of lowering the pH (e.g. using trichlor as the main AF sanitiser), or clarifying the water (a sulphate-free treatment). 3.4 AF Surfaces Feel Slippery. The likely cause is a build up of greasy deposits such as cosmetics, sun cream or body fats. To remedy, clean with a tile and liner cleaner ensuring that it does not contain detergent compounds that could react with chlorine and cause bather discomfort. 3.5 AF Floor AF should be vacuumed at least once a week to remove solids that are not floating in suspension. In fact, some chemicals such as aluminum based clarifier will drop accumulated solids to the bottom of the AF, and vacuuming may even be necessary shortly after treatment. Vacuuming could be done by any one of the following methods: i. Use portable surface vacuuming pump. ii. Use available vacuuming system vian AF wall mounted vacuuming ports. The vacuum equipment is simply a vacuuming pump, which actually could be the circulatory pumps that draw water (suction) together with particles from the AF floor into the AF's filtration system. Connected to the suction port of the pump (placed on AF surface) or the vacuum system is a flexible hose with a vacuum head (flexible roller or brush type) attached to the other end. A telescopic handle could also be fixed to the vacuum head for maneuverability throughout the entire AF floor. Always vacuum systematically. Before starting to vacuum, remember the following things: i. The vacuum head must be connected to the handle and the hose; then placed on the bottom of the AF and the hose filled with water (primed) before connecting to the vacuuming pump or system. ii. Air should be excluded before connecting to the vacuuming pump or system. iii. It may be necessary to switch off the pump to be able to remove the Vacuum hose from the suction source. iv. Never lift the vacuum head from the AF before disconnecting the vacuum hose from the suction source.  14-15 remove these or a strainer basket before the suction port of the vacuuming equipment. Some vacuum head comes with a left trap to trap leaves and large debris. vi. If the floor is exceptionally dirty, discharge the vacuumed water to waste. An automatic AF cleaner can reduce manual cleaning, saving time and money. It enhances clarity and reduces algae growth by moving water in all areas of the AF including those ‘dead spots’ that normal circulation typically misses. 3.6 AF Fittings AF ladders should be checked that they remain sturdy, non- slip, covers hiding fasteners are intact, no sharp edges, no corrosion and no debris and algae build-up. AF gratings, may be made of plastic or stainless steel, should be checked that they remain strong and free of fractures. Fractured grating might give way when stepped upon. They should also be fitting, free of sharp edges and other forms of damage. Algae build-up on gratings causes them to become slippery. Such gratings must be cleaned immediately, following correct procedure and using appropriate cleaning solutions. Prevent algae build- up here Figure 14-6: AF ladder Figure 14-7: Stained AF Floor 3.7 AF Stains AF fittings are usually stainless steel and plastic. Besides cleaning, little maintenance is required. The two common things are: Algae colonies built up at corners and crevices and they can be removed by brushing. Stain caused by rust, algaecides and clarifiers, and they can be removed by brushing. AF decks can also be stained by: Dirt and leaves and they can be removed by pressure washing. Efflorescence, this calcium deposit usually originates from grout or setting mortar. To remove, scrape it off the tile/wall, and/or acid wash it. There are products available which work well for such tasks.  organic; left from a leaf for example, a small amount of granular chlorine added at that location and allowed to settle on the stain will usually remove it instantly. Non- organic stains will not be removed by chlorine. Do not place chlorine tablets directly into the AF because they will stain and etch the plaster. If chlorine doesn't work, acid usually will. Draining and acid washing will remove a thin layer of plaster (and stains), exposing fresh, new looking plaster beneath. A No-Drain acid wash can also be performed, with varying results. Stains can also be sanded with pumice stones or wet/dry sandpaper. Tide mark’ on AF wall at water line is likely caused by a build up of greasy deposits such as cosmetics, sun cream or body fats. To remedy, clean with a liquid commercial tile cleaner ensuring that it does not contain detergent compounds that could react with chlorine and cause bather discomfort. 4 Maintenance of the AF Ground and Complex 4.1 Pre-cleansing Areas - Showers and Footbaths Unless the public are prepared to use the pre-cleansing facilities provided in a civilised way, it will be more difficult to maintain proper standard due to the additional ‘loading’ on the treatment system. In some countries, soaps are provided for foot cleansing and bathing caps are compulsory for public AF. Waste water from the showers and footbaths should be taken to sanitary drainage system. 5 Safety Signs and Notices It is a required to put up safety signs and notices around the AF area. One obvious safety requirement is supervision. When the AF is not supervised by a lifeguard, a clear notice to this effect must be posted prominently to warn bathers. Other prominently posted safety warning notices should include: Depth markers, which are actually floor tiles visibly laid at the AF rim at points of minimum and maximum depths, at all points where the AF floor changes slope, and at appropriate points in between. Notices warning bathers not to dive at shallow depths. Notices informing bathers the location of available first aid supply. Posters providing information on performing cardiopulmonary resuscitation (CPR). Besides signs and notices, it is also required to provide life saving equipment at the AF deck and it includes: Well stocked first aid boxes. Life saving unsinkable rigid foam ring buoy. Life saving line, rope and pole with body hook.