With decades of experience in building swimming pools, Mainstream Pools stresses the importance of regular pool and spa maintenance with the long term benefit being that you and your family can continue to enjoy the pool or spa for years to come.
Pool/Spa water is easily contaminated with algae and bacteria from a variety of sources including wind; top-up water, pets and users.
Untreated or improperly treated pool/spa water can be a health threat. Properly chemically balanced and sanitized water on the other hand, will provide a healthy and visually appealing environment for you, your family and friends.
Controlling these influences is an ongoing requirement and involves chemically balancing the water to ensure it is neutral to users, the pool/spa itself, and the pool/spa equipment.
Regular testing and balancing of your water, sanitizing the water to oxidize contaminants and filtering the water to remove the oxidised contaminants takes little time but ensues that all is well with the pool/spa water.
The following sections deal with each of these requirements and form an easy program for regular pool and spa maintenance.
Your swimming pool/spa is a water Container and the water it contains must be suitable for both:
- The user and
- The container
Balanced water means that its chemical demands are being met.
If the chemical levels are too low, the water will aggressively seek the chemicals and minerals it needs by attacking the pool/spa surface and equipment. This may lead to severe corrosion problems. At the other end of the scale, high chemical levels will precipitate from water and form scale on the pool/spa surface and associated equipment etc.
Out of balance water can cause expensive damage to the pool/spa and may also inhibit the sanitising process
In simple terms, a scientific water balance program suggest that the pool/spa owner should balance the following variables:
- Total Alkalinity
- Calcium Hardness
pH is a measure of how acidic or alkaline the water is, and, the pH scale ranges from 0 to 14, with 7 being neutral. Values below 7 are acidic, and, values above 7 are alkaline.
With pool water we are seeking a pH balance suitable to the safe and healthy human use of the pool/spa, together with the sanitizer being used.
Topping up your pool/spa , rain, heavy bathing loads, and chemical additions can all change the pH level of your pool/spa water.
pH must be kept within the Recommended Ranges, as if it is too high or too low, it may:
- Create swimmer discomfort (itchy skin, red eyes etc.), and/or
- Interfere with the sterilising action of you water sanitiser
pH is the most important aspect of you pool/spa maintenance program
The effect of pH on Chlorine
Effective sanitizing relies on pH values. Therefore, sanitizer and pH levels should be the measurements you check and adjust most often.
Regardless of the chlorine type or chlorination process you use, any pH drift above the “Recommended Range” (7.2 to 7.6 or 6.8 to 7.2 for fibreglass pools) will inhibit the sanitizing effect of your chlorine.
For example, a pH level of 8.2 would mean only about 16% of your chlorine would be available to sanitise the water, which means that you would have to add more than 5 times as much chlorine to achieve the same sanitizing effect. When the pH is lower than 7.0, the chlorine becomes extremely active and is rapidly consumed.
Total Alkalinity (TA)
This is the measure of the bicarbonates, carbonates and hydroxides in your water. The Operational Range is 60 to 200 parts per million (ppm).
Your NSPI Accredited Specialist will advise you of the Recommended Levels to suit your pool/spa and its environment.
Low TA will lead to erosion of the inner surface in concrete and painted pools/spas as the water takes the chemicals it needs from the surfaces.
Low levels will also cause the pH levels to be very unstable with small additions of chemicals resulting in major shifts in the pH values. This is sometimes known as “pH bounce”.
Your Total Alkalinity (TA), can be changed in the following ways;
- Adding “buffer” (ie: bicarbonate of soda), which is used to RAISE the TA
- Adding “acid” to the water to lower pH, will also LOWER the TA
- Adding “Top-up” water may change the TA (depending on the quantity and the TA of the top-up water itself).
The Interconnection between pH and Total Alkalinity
From the last section, it can be seen that acids will lower both pH and TA, as there is an interconnection between these two chemical components, and because of this, they need to be always adjusted together.
The levels you are seeking to maintain are:
- A pH of 7.2 to 7.6 (or 6.8 to 7.2 in a fiberglass pool), and
- A Total Alkalinity of about 100ppm (or, as directed by you SPASA Member).
Let’s have a look at the interconnection, and assume that the pH is OK but the TA is low.
- To raise the level of the TA, you must add, “Buffer” (Sodium Bicarbonate) at the required rate. However, “Buffer” is an alkali, and will also raise pH, and “Acid” (used to lower pH), also lowers TA.
The idea is to raise TA artificially high, so that when the “acid” is added (to lower the pH to the recommended range), the TA is also reduced.
Remember – do not try to do it all in one go – allow 6 to 8 hours between adjustments, testing each time.
Two “acid” types are used to lower pH. One is Hydrochloric Acid (Spirits of Salts), and the other is Sodium Bisulphate. Both of which will effectively lower the pH and TA.
Check with your NSPI Accredited Specialist as to which type is most suitable for you and your pool/spa. If using Hydrochloric Acid to lower the pH, it is vital that it be diluted (one part of acid to ten parts of water), prior to adding to the water.
Note that the filler should be running during these additions, and, for about one hour afterwards to ensure adequate mixing.
No other type of “acid” should ever be used for pH or TA adjustments.
In simple terms, measure the amount of dissolved calcium in your pool/spa water. The desired range is 80 to 500 ppm; however, you should consult with your NSPI Accredited Specialist for the specific requirements of your particular pool/spa finish, water supply, environment and equipment.
Both Total Alkalinity and Calcium Hardness need to be brought into balance, if not;
- Low levels will mean that the water is corrosive to the pool and or equipment, and
- High levels will lead to the scale formation on the pool equipment
A normal water test kit cannot perform measurement of Calcium Hardness, and we would suggest that a water sample be taken each month to an NSPI Accredited Specialist for testing. A rough rule of thumb in areas where calcium levels are not naturally high is that testing annually will suffice after the initial adjustment.
The only exception to this is; if you use Calcium Hypochlorite (65% Chlorine) to sanitise your water, and, depending upon the method used – this chemical can quickly raise Calcium Hardness levels, and may require more frequent testing and adjustment.
Chlorine is the most commonly used water sanitizer in the world, and, there are many forms of this highly effective product, including;
- Cranular Chlorine (calcium hypochlorite – 65% active)
- Liquid Chlorine (sodium hypochlorite – 10/15% active)
- Sablised Chlorine (in two forms);
- “Dichlor” granular chlorine (approx. 60% active), and
- “Trichlor” slow dissolving tablets (approx. 905 active), and
- Salt Water Chlorinators (electronic units which produce chlorine by the electrolysis of salt in the pool water)
Whatever form of chlorination you use, for it to work efficiently, the pH must be within the Recommended Range.
Queensland Health recommend chlorine levels be maintained at;
- At least one (1) part per million of Free Available Chlorine in an unstabilised pool/spa, or
- A least two (2) parts per million Free Available Chlorine in a stabilised pool/spa
Free Available Chlorine can be tested with a test kit.
Utlra-violet light attacks chlorine, and “stabilizing” the water involves adding the chemical Cyanuric Acid, which reduced the amount of chlorine destroyed by sunlight. Up to 5 parts per million of free available chlorine can be destroyed in three hours of strong sunlight.
For health and financial reasons, it is important to overcome this effect as much as possible, and so stabilizing the water is strongly recommended.
For the initial stabilizing of a new pool/spa, Cyanuric Acid should be added to achieve the recommended level of 30 to 50 parts per million.
Stabiliser is lost through splash-outs and by backwashing the filter, and, will need to be replaced regularly, especially during the summer season. To do this, it is necessary to first test for the residual levels in the water.
NSPI Accredited Specialists can do this testing from a water sample, and, based on your pool/spa volume, can recommend how much stabilizer to add.
As you only need stabilizer occasionally, fix the correct level at the beginning of the summer season and then check it every few months during the year. Naturally, if you have to pump out the water, or lose a lot through slash-outs or backwashing, more frequent testing and adjustments may be required.
Any Chemical Additions
As a general rule, you are far better off adding small amounts of chemicals whilst running the filter, and testing the effects after several hours. Attempting large chemical changes by adding large amounts of chemicals can result in big problems.
The Filtration Process
So far, the treatments have dealt with the chemical destruction of water contaminants. “Filtration” is the physical removal of neutralized contaminants (chemical and human wastes), together with the insoluble particles from the water.
Daily filtration cycles should be in the order of 6 to 8 hours (depending on the size of the system installed), to ensure that at least (1) one “turnover” is achieved (that is, as a minimum, the equivalent litreage of the pool/spa is filtered each 8 hours).
Additionally, the filter should be running during periods of use (and for a short time after), to skim body oil from the water, and, to add some chlorine (if an automatic chlorinator is fitted).
Remember that when the pool/spa is being used, there is a high chlorine demand, due to the user contamination of the water.
The Filtration System
While filtration system may differ in regard to their type, they will all have the following basic features:
- A Skimmer into which the inflow carries surface debris (leaves, oil, dust etc), into the start of the filtration system,
- An initial Leaf Basket in the skimmer to trap leaves and large debris, before the water is suck through the pump,
- A Secondary Basket in the hair and lint pot, in front of the pump,
- A circulating Pump,
- A Filter which physically removes solids from the water, and
- Pipework through which the clean water is returned to the pool.
To prevent rubbish inhibiting the water flow and causing pump starvation), these items need to be checked and cleaned regularly.
Types of Filters
All filtration relies on removing solid matter from the water as it is pumped through the filtration system.
There are three popular types of filtration systems currently in use in Queensland:
- Diatomaceous Earth (or DE Filter)
- Sand Filter
- Cartridge Filter
All three types have high flow characteristics, and are highly efficient. However, they all require cleaning to remove the entrapped solids, and failure to clean filters (as required) will result in reduced filtration flow, because of the accumulated debris blocking the filter medium.
Regular cleaning (as indicated by the pressure gauge) is essential. Failure to clean filters can also cause an increase in pressure within the filter tank, which will reduce the life expectancy of the unit.
Cleaning methods will depend upon the filter type. Both DE & Sand Filters can be “backwashed” (which is to reverse the flow of water through the filter tank, and flush the rubbish to waste).
Cartridge Filters require hosing down, and soak in the correct cartridge cleaning fluid.
Regular cleaning of a filter will provide benefits in terms of better water flows for filtration & vacuuming, and, better chlorination, and, better circulation within the pool, due to the increase flow rate.
In addition to this regular cleaning, periodic service of the filter is recommended to remove any build up of grease and scale. This can be arranged through your NSPO Accredited Specialist.
Automatic Chlorination Systems
The cleaning and maintenance of these automatic system is most important, to ensure that they continue to function up to their designed standards of performance.
In its normal use, a Salt Water Chlorinator (due to the electrolytic action which converts salt to chlorine within the cell) attracts calcium (and other contaminants in the water), which adheres to the cell mesh and which will interfere with the chlorine production of the unit, and eventually reduce the expected life of the unit.
Check and clean the cell, only in accordance with the manufacturer’s recommendations.
NEVER MIX CHEMICALS – this could lead to an extremely violent reaction (explosion!), and/or the production of Toxic Fumes. Do not even use the same bucket for diluting different chemical, as; even different chlorides can react violently when mixed together.
When transporting chemical in your car, do so in a manner that prevents them mixing in the event of a spillage or an accident, and, secure all containers firmly.
Store chemicals so that any accidental breakage or leakage cannot cause a mixing of pool chemicals, or, a mixing of a pool chemical with any other stored substance.
Some pool chemicals can cause nasty burns or be poisonous, and you should always store them securely away from the children or pets can get at them. You should also use protective gloves, clothing and eyeglasses when handling.
Always add the chemical to a bucket containing water – not the other way around. To add water to a chemical is potentially dangerous. Dilute all pool chemicals with water by at least 1:8 prior to adding to the pool.
Gave the filter running when you are adding chemicals to the pool water to ensure proper mixing and distribution.
Always read the instruction on the labels of the pool chemicals and other products – and, follow them carefully.