Resources

Not only do we want to protect the swimmers, we want to protect the pool and equipment. Pools, pumps and filters are very expensive and so need to be preserved as long as possible. Keeping the proper water balance is essential to their protection and long life.

Water balance

“Water balance” means water at these levels:

pH of 7.4 – 7.6

Total alkalinity 80 to 140 (depending on type of pool)

Calcium hardness 200 to 400 ppm

When the pH , total alkalinity and calcium hardness are all within the recommended ranges the pool is said to be in balance. To keep the pool in balance requires regular testing and maintenance. It’s very important to discover problems early. The earlier the problem is detected, the easier and less costly the solution (in labor, chemicals and repairs).

It is recommended that you keep accurate records of chemical additions – dates added, amounts, results, etc. This helps you become familiar with your pool’s characteristics and enables you to identify abnormal conditions easier and faster.

pH

Solutions can be acidic or basic (alkaline). pH is a value that indicates how acidic or basic a solution is. The scale for pH ranges from zero (0) to fourteen (14). The ideal pH for pools is 7.5, the ideal range is 7.4 – 7.6. The minimum and maximum is 7.2 – 7.8.

Low pH will cause:

Etched plaster, Corroded metals, Stained plaster, Eye & skin irritation, Destruction of total alkalinity and liner wrinkling

High pH will cause:

Scale formation, Cloudy water, Short filter runs, Eye & skin irritation, Poor chlorine efficiency

Total alkalinity

To exercise proper pH control one needs to understand total alkalinity. Among other things water contains alkaline materials. The “water source” affects the alkalinity and thus varies from location to location. Total alkalinity is a measure of the total amount of alkaline materials dissolved in the water. It is said to be the buffering capacity of the water, the water’s resistance to change in pH. It is also described as the water’s ability to neutralize acid. The thing to remember is that low or high total alkalinity can cause serious problems that may require expensive remedies.

There is a relationship between pH and total alkalinity. Acid and some other acidic pool chemicals lower pH. Soda ash, sodium bicarbonate, and other basic (alkaline) pool chemicals raise pH. Low total alkalinity results in fast and easy pH change. High total alkalinity results in slow and difficult pH change.

Total alkalinity is measured in parts per million (ppm). The ideal range is from 80 – 140 ppm depending on the type of pool. Plaster pools proper range=80 ppm – 120 ppm. Vinyl liner pools proper range=100 ppm – 140 ppm.

Low total alkalinity problems:

Etched plaster, Corroded metals, Stained plaster, pH bounce, Eye & skin irritation and liner wrinkling

High total alkalinity problems:

Scale formation, Cloudy water, Hard to change pH, Eye & skin irritation, Poor chlorine efficiency

To raise total alkalinity and pH:

Use TA+

To lower total alkalinity and pH:

Use PH or Pool Acid

Note: Acid combined with chlorine produces toxic mustard gas, AVOID!!!

Three areas of consideration in proper pool maintenance.

– Filtration and circulation

– Disinfection, sanitation, oxidation

– Water Balance

Filtration and circulation: If the water is not effectively being filtered and circulated, then all the chemicals and good advice and knowledge will be of little or no benefit in proper pool maintenance. Filtration and circulation involve proper sizing of pump, proper sizing of filter, and maintaining the filter. If the pump is too small, or not run long enough each day, or the filter is too small, or old, or broken then you can count on problems in water quality.

Also the circulation jets should all be pointing 45 degees down and in the same direction to maximise flow.

Disinfection, sanitation, oxidation: The chief area of concern here is to protect the swimmers from disease. Oxidizing away organic matter is a secondary consideration.

Water Balance: The concern here is to protect the equipment and the pool. Plaster etching, metal, corrosion, staining and swimmer discomfort results when the pH is too low. And when the pH is too high the results are scaling on the pool walls and bottom and equipment, poor sanitizer efficiency and swimmer irritation.

With a basic knowledge of these three areas of concern and a consistant maintenance schedule you can keep your pool and spa in good running order. Remember that an ounce of prevention is worth a pound of cure and this is a big “truth” in the area of pool and spa maintenance.

Our online glossary covers the complete terminology needed to understand many of the concepts discussed within our Aquatic tips directory.

Note: All information provided by “No Green Pools” is to help educate the reader in pool maintenance. Any use and application of this information is the responsibility of the reader/user. “No Green Pools is not responsible in any way for the consequences of using/applying the provided information and suggestions.

Disinfecting

Sanitize:

By sanitize we mean to kill all living organisms.

Disinfect:

By disinfect we mean to kill all disease – causing organisms.

Oxidize:

To destroy ammonia, nitrogen – containing contaminants and swimmer waste.

Protection for swimmers!

The chief concern here is to protect the swimmers from disease, and there are regulations relative to commercial pools and spas that must be adhered to or you will be shut down.

As bacteria, algae and other organic matter is introduced to the water there needs to be an immediate instantaneously killing action by the proper chemicals. Therefore, there needs to be a “residual” of the proper chemicals in the water at all times. That “residual” is measurable and must remain at a certain level at all times.

The most commonly used sanitizer is Chlorine. When a chlorinating compound is added to water, it forms the killing form of chlorine which is hypochlorous acid. Hypochlorous acid is measured as a residual in water as free available chlorine or free chlorine.

As the chlorine destroys bacteria and algae, the chlorine itself is partially destroyed or reduced. Direct sunlight, splashing and low pH also acts to dissipate or use up the chlorine. Chlorine reacts with ammonia and nitrogen – containing contaminants, such as persperation, urine and other swimmer waste to produce combined chlorine or chloramines. Chloramines are less effective than free chlorine and usually have a foul smell and can be a body and eye irritant. This foul smell is most often noticed around very active community or commercial pools. The smell is an indication that the free chlorine has been used up and is now in the form of the much weaker chloramine. We advise that you use a test kit that measures Free available chlorine. These kits use DPD reagents that turn various shades of pink through red in the presence of free available chlorine.

To maintain the chlorine at a safe level, regular testing and chlorine additions are necessary. Summer requires more testing and adding of chlorine.

Superchlorinate or Shock? Which to do?

Superchlorination refers to the adding of a megadose or superdose of chlorine to the water to kill everything and oxidize all of the ammonia, nitrogen compounds and swimmer waste. This is often needed following heavy usage or after rainfall to restore the chlorine residual to the desired level.

Shocking refers to adding a non-chlorine compound to the water to oxidize all of the ammonia, nitrogen compounds, and swimmer waste without killing anything. This would not affect the pH like superchlorination and swimmers can return to the water within 15 minutes after a “shock” treatment, whereas there should be a longer wait after superchlorination.

Stabilized chlorine

Refers to chlorine compounds that contain cyanuric acid which protects the chlorine in the water from being destroyed by the ultraviolet rays of the sun. Dichlor and Trichlor are the two types of stabilized (conditioned) chlorine.

Sodium dichlor

One of the stabilized chlorine compounds. Provides approximately 62% – 63% available chlorine. It is white, granular, fast – dissolving and has a near – neutral pH (6.5-7.0). Dichlor can be used for regular as well as superchlorination and it has a very long shelf life.

Trichlor

The other stabilized chlorine compound provides approximately 89% – 90% available chlorine. Available in 1-inch tablets, 3-inch tablets, sticks or in a granular form. Trichlor is very slow – dissolving and it is acidic with a pH of 2.8 – 3.0. With the acidic nature of this compound it is wise to check the water’s total alkalinity more often during the swimming season. Due to slow – dissolving characteristic trichlor cannot be used for superchlorination. Advantages of trichlor tablets include constant and effective chlorination, low acidic demand, ease of handling and indefinite shelf life. The granular form of trichlor is used mostly as a spot algaecide in plaster pools.

(Caution: Do not mix different types of chlorine. For example do not mix trichlor and calcium hypochlorite. The result can be an explosion or fire with the evolution of toxic chlorine gas.)

Calcium Hypochlorite

Does not contain stabilizer ( cyanuric acid or conditioner). Cal-hypo is a white powder or granule with a high pH (11.8). It provides 65% available chlorine. Because this product contains calcium it will cloud the water temporarily upon addition. When using cal-hypo as a regular chlorinating source it is important to monitor the pH , total alkalinity and water hardness levels more closely. High pH, high alkalinity and water hardness results in scale formations. Proper storage is important and critical.

Sodium hypochlorite (liquid chlorine)

Provides 10%-12% available chlorine and does not contain stabilizer (conditional or cyanuric acid). It has a high pH (13) and may require the adding of muriatic acid to bring the pH down. Used for regular and superchlorination.

Note: Conditioner

(Chlorine stabilizer, cyanuric acid) Can be added to the pool water to protect cal-hypo and liquid chlorine from UV rays thus giving these chemicals longer life.

Filtration:

What’s the purpose of filtration? the purpose of filtration is to remove matter (particles) held in suspension in the pool / spa water.

What are the different types of filtration methods for pool / spas? There are three types of media for pool /spa filtration systems:

• Sand

• Diatomaceous earth (DE)

• Cartridge filters

Which media is the best? All three are being used successfully. Each has its own unique advantages and disadvantages.

What problems can improper filtration cause? Cloudy water, higher cost in labor and chemicals, to name a few.

What kind of maintenance is required relative to filtration? Regular monitoring is required regardless of the system you have. Sand and DE filters require backwashing and replacement of media. Cartridge filters require cleaning and replacement of cartridges.

Circulation:

Is proper circulation important? Yes! Circulation of water is very important to proper filtration and water maintenance. Without proper circulation the filtering system cannot work properly and the chemicals cannot be dispersed throughout the pool. Improper circulation can result in water maintenance headaches and higher cost due to increase in labor and chemicals. Attention, therefore, needs to be given to flow rates and turnover rates. The flow rate, the rate of flow through the recirculation system, can be too low or too high. Proper turnover rate, the time required to recirculate the entire volume of water in a swimming pool or spa, is essential to ensure optimum water clarity.

What can affect circulation in a negative way? Some of the things that can affect circulation negatively:

Improper pump size, Improper plumbing, Improper filter size, Clogged skimmer baskets, Clogged filters

These are just a few examples of what can cause these types of problems.

Acid:

A chemical substance that provides hydrogen ions. It has the ability to dissolve metals, neutralize alkaline materials and combine with bases to form salts. Acid lowers the pH and alkalinity of water. Examples = muriatic acid (hydrochloric) and dry acid (sodium bisulfate).

Acid demand:

The amount of acid required to bring high pH and total alkalinity down to proper levels. The amount of acid required is determined by the acid demand test.

Algae:

Microscopic member of the plant kingdom, nourished by carbon dioxide and use of sunlight to carry out photosynthesis. Introduced by rain or wind and grows in colonies. Algae is a nuisance in swimming pools and spas because it can harbor bacteria and is slippery. Most common pool types are black, blue green, green and mustard. Maintaining proper sanitizer levels, shocking and superchlorination will help prevent its occurrence.

Algaecide:

A chemical designed to kill, destroy or control algae.

Alkali:

(also called base) – A class of compounds which reacts with acid to give salt. Alkali is the opposite of an acid.

Alkalinity:

Total alkalinity is a measure of the pH-buffering capacity of water. It tells us the water’s resistance to change of pH. This is one of the basic water tests necessary to determine if the water is in balance.

Available chlorine content (ACC) percentage:

A measure of the relative sanitizing and oxidation strengths of different pool chlorine sanitizers. The measure is relative to chlorine gas which has been given the value of 100%. Some compounds are 10%, some 35%, some 65%, some 90%.

Backflow:

The backing of water through a pipe in the direction opposite to the normal flow.

Backwash:

The process of cleaning the filter by reversing the flow of water through it with the dirt and rinse water going to waste.

Bacteria:

The single-celled microorganisms of various forms, some of which are potentially disease-causing. Bacteria are controlled by chlorine or other sanitizing and disinfecting agents.

Baking soda:

Sodium bicarbonate. A white powder used to raise total alkalinity with little effect on pH.

Balanced water:

The water is said to be balanced when pH, total alkalinity and calcium hardness are within their proper levels.

Base:

Alkali, the opposite of acid.

Base demand:

The amount of pH increaser (sodium carbonate) needed to raise the pH to desired levels.

Breakpoint chlorination:

The process of adding sufficient free available chlorine or other oxidant (i.e., persulfate) to chemically convert chloramines and ammonia-nitrogen compounds to inert nitrogen gas.

Calcium chloride:

A soluble white salt used to raise the calcium or total hardness level in the pool or spa water.

Calcium hardness:

The calcium content of water. When too low, the water is corrosive. When too high, the water becomes scale forming. One of the basic tests necessary to determine water balance. Ideal range is 200-400 ppm.

Calcium hypochlorite:

A compound of chlorine and calcium used as a disinfectant, sanitizer, bactericide, algaecide and oxidizer in pool and spa water. It usually contains 65% available chlorine.

Chelate:

The process of preventing metals in the water from combining with other components in water to form colored precipitates that stain pool surfaces and produce colored water.

Chelated copper:

Copper algaecides containing ingredients to prevent the copper from staining the pool surfaces and coloring the water.

Chloramines:

Undesirable, foul-smelling, body-irritating compounds formed when insufficient levels of free chlorine react with ammonia and other nitrogen-containing compounds (swimmer and bather waste, perspiration, urine, etc.). Chloramines are removed by superchlorination or shock treating.

Chlorine:

A disinfectant added to swimming pool or spa water to destroy and inhibit bacterial and algal growth in addition to oxidizing unwanted organic and nitrogenous waste.

Chlorine demand:

The amount of chlorine needed to oxidize all organic matter (bacteria, algae, chloramines, ammonia and nitrogen compound) in pool/spa water.

Chlorine residual:

The amount of chlorine left in the pool/spa water after the chlorine demand has been satisfied.

Clarifier:

(also called coagulant or flocculant) – A chemical compound used to gather suspended particles so they may be removed by vacuuming or filtration.

Clarity:

The degree of transparency of the water.

Combined chlorine (CC):

(chloramines) – Undesirable, foul-smelling, body irritating compounds formed when insufficient levels of free available chlorine react with ammonia and other nitrogen-containing compounds (swimmer’s waste). Combined chlorine or chloramines are still chlorine, but in a very weak state. It can thus be measured as chlorine.

Conditioner (stabilizer):

Cyanuric acid. It slows down the degradation of chlorine in the water by sunlight.

Corrosion:

The etching, pitting or eating away of the pool or spa or equipment. Caused by improper water balance, misuse of acid or acidic products or from soft water.

Cyanuric acid (conditioner or stabilizer):

Protects chlorine in the water from being destroyed by sunlight.

D.E.: Diatomaceous earth.

Defoamer (anti-foam):

A chemical added to the water to make the suds or foam go away. These products do not remove the source of the sudsing. Most often, the water must be drained and refilled to remove the soaps, oils and other causes of foaming.

Diatomaceous earth (D.E.):

White powder composed of fossilized skeletons of one-celled organisms called diatoms. These skeletons are porous and have microscopic spaces. D.E. is the filter medium for Diatomaceous earth filters.

Dichlor:

Sodium dichlor. A fast-dissolving chlorine compound containing chlorine and cyanuric acid (stabilizer or conditioner). pH of 6.5-7.0

Disinfect:

To kill all pathogenic (disease causing) organisms.

DPD:

An indicator agent used for measuring free chlorine and total chlorine.

Dry acid:

Sodium bisulfate. A dry white crystal that produces acid when added to water. Used for lowering pH and total alkalinity. Safer to handle than muriatic acid.

Filter:

A device that removes undissolved or suspended particles from water by recirculating the water through a porous filter medium. Three types used in pools and spas are sand, cartridge and D.E. filters.

Filter area:

The total surface area of the filter medium that is exposed to the flow of water from the pump, expressed in square feet.

Filter cartridge:

A replaceable porous element made of paper or polyester used as the filter medium in cartridge filters.

Filter septum:

The portion of the filter element consisting of cloth, wire screen or other porous material on which the filter medium or filter aid is deposited. The nylon grid on a D.E. filter is the septum.

Filtration rate:

The rate at which the water is traveling through the filter, expressed in U.S. gallons per minute (gpm) per square foot of filter area.

Flocculation:

The combining or coagulation of suspended particles in such a way that they form small clumps (floc).

Flow rate:

The quantity of water flowing past a designated point within a specified time, usually expressed as gallons per minute (gpm).

Free available chlorine:

Chlorine that is not combined. This is the chlorine available to sanitize or disinfect the water.

Ground-fault circuit-interrupter (GFI):

A device intended to protect people. It interrupts (de-energizes) the electrical circuit whenever it detects the presence of excess electrial current going to ground (usually 1/40th of a second and 5/1000th of an ampere). Hydrochloric acid:

Muriatic acid. A very strong acid used in pools to lower pH and total alkalinity. Use extreme care in handling.

Hypochlorite:

The family of chlorine-containing compounds, including calcium hypochlorite, sodium hypochlorite and lithium hypochlorite, that are used as disinfectants and sanitizers in pool and spa water.

Hypochoris acid:

The by-product produced when elemental chlorine or other chlorinating compounds react with water. The most powerful disinfecting form of chlorine in water. Sometimes called the killing form of chlorine.

Isocyanurates:

Family of chlorine pool sanitizers that contain conditioner (cyanuric acid). Dichlor, trichlor.

Liquid chlorine:

A sodium hypochlorite solution. Usually provides 10 to 12% available chlorine, has a pH of 13 and requires that small amounts of acid be added to the pool to neutralize the high pH. Good for regular chlorination and superchlorination.

Lithium hypochlorite:

A dry, granular chlorinating compound with an available chlorine content of 35%. Rapid-dissolving.

Micron:

A unit of length equal to 1 millionth of a meter. Microns are used to describe the size of the pores or openings in filter media. Sand filters have openings of 25 to 30 microns; cartridge filters have openings of 8 to 10 microns; and D.E. filters have openings of 1 to 5 microns. A granule of table salt is between 90 and 110 microns.

Muriatic acid:

(31-45% hydrochloric acid). Used to reduce the pH and alkalinity levels in pool water. It is also used in acid washing, a process that removes stains and scale from pool plaster.

Nitrogen:

A gas that causes algae to bloom and disables chlorine. Nitrogen is brought into the water each time it rains. Maintaining proper chlorine levels will prevent nitrogen from becoming a problem. Superchlorination is practiced to remove nitrogen and its related compounds.

Non-chlorine shock:

A term given to a group of chemical compounds that are used to oxidize or shock the water (destroy ammonia, nitrogen and swimmer waste). They contain no chlorine and do not kill living organisms.

Organic waste (swimmer waste):

The soap, deodorant, suntan lotion, lipstick, makeup, cologne, body oils, perspiration, spit, urine, etc., brought into the water. They form chloramines when an insufficient amount of chlorine is added to the water. Requires large amounts of chlorine or non-chlorine shock to destroy.

Oxidation:

To rid the water of ammonia, nitrogen compounds and swimmer waste. Removal is accomplished by superchlorination or by shock treating with a non-chlorine oxidizer.

Oxidizer:

A non-chlorine shocking compound that removes or destroys built-up contaminants and chloramines in pool water without raising chlorine levels as required when “superchlorinating.”

pH:

A term used to indicate the level of acidity or alkalinity of pool water. Ideal range is 7.4 to 7.6.

ppm:

parts per million. Chlorine, for example, should be kept between 1.0 and 3.0 ppm; total alkalinity should be between 80 and 120 ppm; and calcium hardness should be between 200 and 400 ppm.

Pump capacity:

The volume of liquid a pump is capable of moving during a specified period of time. Usually expressed in gallons per minute (gpm).

Pump strainer basket:

(hair and lint trap) – A device placed on the suction side of the pump which contains a removable strainer basket designed to trap debris in the water flow without causing much flow restriction.

Quaternary ammonium compounds (quats):

Chemical compounds of ammonia used as algaecides and algaestats.

Reagents:

(pronounced re-Agents) – The chemical agents, dyes, indicators or titrants used in testing various aspects of water quality.

Scale:

The precipitate that forms on surfaces in contact with water when the calcium hardness, pH or total alkalinity levels are too high.

Sequestering agent:

(chelating agent) – A chemical that will combine with dissolved metals in the water to prevent the metals from coming out of solution and causing stains.

Shock treat:

The adding of a significant amount of oxidizing chemicals to the water to destroy ammonia and nitrogen compounds or swimmer waste. Some say this is the same as superchlorinating. Some differentiate “shocking” from superchlorinating in that they use a non-chlorine compound to “shock” without adding chlorine to the water. Swimmers can return to the water sooner.

Silt:

Soil particles having diamters between 0.004 and 0.062 mm (millimeters). Where the particles are too small to be filtered, clarifiers are used to coagulate the particles into clumps large enough to be filtered.

Soda ash (sodium carbonate):

A chemical used to raise the pH and total alkalinity in pool and spa water.

Sodium bicarbonate (baking soda or bicarb):

A chemical used to raise the total alkalinity in pool and spa water with only a slight effect on the pH.

Sodium bisulfate (dry acid):

A chemical used to lower the pH and total alkalinity.

Sodium carbonate:

Soda ash, used for raising pH and total alkalinity in pool and spa water.

Sodium dichlor (Dichlor):

A fast dissolving, granular, stablized organic chlorine compound providing either 56% or 63% available chlorine. Used for regular as well as superchlorination.

Sodium Hypochlorite (liquid chlorine):

Usually provides 10% to 12% available chlorine; has a pH of 13. Does not contain conditioner or stabilizer to protect it from sunlight.

Sodium persulfate:

Active ingredient and chemical name of a non-chlorine shock treatment or non-chlorine oxidizer. Does not kill bacteria or algae, but will oxidize or destroy ammonia, nitrogen and swimmer waste.

Sodium sulfite:

A chemical used to neutralize or de-chlorinate pool and spa water.

Soft thiosulfate:

A chemical used to neutralize or de-chlorinate pool and spa water.

Soft water:

Water that has very low calcium and magnesium content, usually less than 100 ppm or 6 grains.

Stabilized chlorine:

A family of chlorine pool sanitizers that contain conditioner (cyanuric acid) to protect the chlorine from the degrading UV rays in sunlight.

Stabilizer:

Also called a conditioner. Cyanuric acid. It slows down the degradation of chlorine in the water by sunlight.

Stain inhibitor:

Also called sequestering or chelating agent. A chemical that will combine with dissolved metals in the water to prevent the metals from coming out of solution causing staining.

Superchlorination:

Adding an extra large dose (5 to 10 ppm) of chlorine to the water to destroy ammonia, nitrogen and swimmer waste. It is the water’s resistance to change in pH.

Total chlorine:

The sum of “free available” and “combined” chlorine.

Total dissolved solids (TDS):

A measure of the total amount of dissolved material in the water. Maximum amount in pools is 2500 ppm. Maximum in spas is 1500 ppm over starting TDS. To lower TDS, drain water out.

Trichlor:

A slow-dissolving, tableted or granular, stablized organic chlorine compound providing 90% available chlorine. Trichlor has a pH of 2.8.

Turbity:

The cloudy condition of the water due to the presence of extremely fine particles in suspension that cannot be trapped by the filter because they are too small. Adding a clarifier will make the filter more efficient.

Turnover rate:

The period of time (usually in hours) required to circulate a volume of water equal to the volume of water contained in the pool or spa. Pool capacity in gallons, divided by pump flow rate in gallons per minute, divided by 60 minutes in 1 hour, will give hours for 1 turnover.