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The Little Water Manual

KS4,3 Acidity is also known as m-Alkalinity, Total Alkalinity, Hydrogen Carbonate Hardness, Acid Buffering Power, Temporary Hardness, … Alkalinity describes the ability of water to buffer the increase of ph value influencing chemicals (flocculants, disinfection media – e.g. chlorine products – lowering or raising pH). To provide a sufficient buffering effect, alkalinity should amount to at least 0.7 mol/m3 and/or mmol/l. This value represents the hydrogen carbonated materials dissolved in water. The buffering effect in the 4.2 – 8.2 pH range relies on a balance between hydrogen carbonate ions and carbon dioxide dissolved in water. Should chemicals that lower the pH value of water be added (acids), then the hydrogen carbonate ion combines with these to form carbonic acid (which in turn dissolves into carbon dioxide and water) and water. At a 4.3 pH value all hydrogen carbonate ions are depleted; thus the KS4,3 Acidity designation. Should in contrast chemicals be added that raise the pH value (bases), then hydrogen carbonate ions form again out of dissolved carbon dioxide and water. The modified relationship between dissolved carbon dioxide and hydrogen carbonate ions thus determines a new pH value. The buffering capacity of water becomes too low at alkalinities below 0.7 mmol/l, thus making it difficult to determine the pH value. In such cases small amounts of acids and bases will immediately and intensively change the pH value. Furthermore, water will have a corrosive effect on pipe mains. A too low alkalinity value can be increased through the addition of sodium hydrogen carbonate and/or sodium carbonate. When alkalinity values are high, however, the buffering effect is too large and large amounts of pH regulators are needed in order to achieve a change in pH. Additionally, when conditions are unfavorable (warming, pH > 8.2), calcium tends to precipitate because carbonate ions form out of hydrogen carbonate ions which in turn form water-insoluble compounds in the presence of calcium or magnesium (see Total Hardness). Alkalinity that is too high can be corrected through – at least partial – replacement of water. Pool-i.d. offers both test strips and a tablet count process (SVZ500) to measure this important water parameter. Because pH values above 8.2 will stop the equilibrium between hydrogen carbonate ions and carbonate ions, the alkalinity of the water must then (pH value over 8.2) be measured with the Alkalinity-p Method.
In Northern latitudes, active oxygen is a particularly popular alternative disinfectant to chlorine. Principally, however, - for purposes of measurement – what counts is whether the medium used contains persulfate or peroxide. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 – Method (e.g. Pooltester PT200). When using peroxide containing disinfection media, Hyd. Peroxide tablets are used in connection with the acidifying PT-tablets (e.g. PT300; hydrogen peroxide method). In both cases, the “Active Oxygen (O2)“ designation is in fact misleading. It is not the molecular Oxygen that oxidizes (disinfects); rather it is an Oxygen radical which quite quickly combines with an additional radical to form molecular Oxygen (the air one breaths). This is also the main disadvantage to this method; because the disinfection effect does not last long and the effect is rather limited. As a strict rule, therefore, Chlorine is added in regular intervals when Active Oxygen is used for disinfection. Yet with the DPD N° 4 – Method false readings can then result (when simultaneously using both Chlorine and Active Oxygen), because the potassium iodide contained in this tablet catalytically splits the persulfates and thus the sum of persulfate and chlorine is indicated
KS4,3 Acidity is also known as m-Alkalinity, Total Alkalinity, Hydrogen Carbonate Hardness, Acid Buffering Power, Temporary Hardness, … Alkalinity describes the ability of water to buffer the increase of ph value influencing chemicals (flocculants, disinfection media – e.g. chlorine products – lowering or raising pH). To provide a sufficient buffering effect, alkalinity should amount to at least 0.7 mol/m3 and/or mmol/l. This value represents the hydrogen carbonated materials dissolved in water. The buffering effect in the 4.2 – 8.2 pH range relies on a balance between hydrogen carbonate ions and carbon dioxide dissolved in water. Should chemicals that lower the pH value of water be added (acids), then the hydrogen carbonate ion combines with these to form carbonic acid (which in turn dissolves into carbon dioxide and water) and water. At a 4.3 pH value all hydrogen carbonate ions are depleted; thus the KS4,3 Acidity designation. Should in contrast chemicals be added that raise the pH value (bases), then hydrogen carbonate ions form again out of dissolved carbon dioxide and water. The modified relationship between dissolved carbon dioxide and hydrogen carbonate ions thus determines a new pH value. The buffering capacity of water becomes too low at alkalinities below 0.7 mmol/l, thus making it difficult to determine the pH value. In such cases small amounts of acids and bases will immediately and intensively change the pH value. Furthermore, water will have a corrosive effect on pipe mains. A too low alkalinity value can be increased through the addition of sodium hydrogen carbonate and/or sodium carbonate. When alkalinity values are high, however, the buffering effect is too large and large amounts of pH regulators are needed in order to achieve a change in pH. Additionally, when conditions are unfavorable (warming, pH > 8.2), calcium tends to precipitate because carbonate ions form out of hydrogen carbonate ions which in turn form water-insoluble compounds in the presence of calcium or magnesium (see Total Hardness). Alkalinity that is too high can be corrected through – at least partial – replacement of water. Pool-i.d. offers both test strips and a tablet count process (SVZ500) to measure this important water parameter. Because pH values above 8.2 will stop the equilibrium between hydrogen carbonate ions and carbonate ions, the alkalinity of the water must then (pH value over 8.2) be measured with the Alkalinity-p Method.
Biguanide disinfectants are also gaining in popularity as an alternative to chlorine. Other than with other substitute materials, such as for example ozone or active oxygen, biguanides do not go well with chlorine, bromine, copper, or silver compounds. Nevertheless a counteracting agent is required because biguanides do not deploy an oxidative effect which is required, for example, for the breakdown of organic materials such as ureas and sweat. To do this, as a rule, hydrogen peroxide (H2O2) is used in addition to biguanide which is why Pool-i.d.’s Pooltester PT300 is standardized to measure both values at the same time together with the pH value.
Using bromine as a disinfectant is becoming a popular alternative to chlorine. The advantage of this method is that combined bromine is unscented compared to combined chlorine (chloramine). That is, the disinfection effect is the same but human mucous membranes are not irritated. Disadvantages to the use of bromine products include, however, the limited oxidation effect and the higher prices and handling risks. Often a combination of bromine and chlorine is used; but this makes determining the concentration difficult. Under the DPD N° 1-Method, measurements now show (if chlorine is used with bromine) the total concentration of free and total bromine and free chlorine. In order to establish the bromine concentration in this special case, the free chlorine must be converted into combined chlorine with the aid of DPD-glycine (Tablets or Powder-Pack). In contrast to chlorine, the confirmation “DPD N° 1” reagent works both with free and with combined bromine, thus always establishing the total bromine content.
Basically dissolved salts belonging to the alkaline earth elements calcium and magnesium are found in non-distilled water. In rare cases, strontium and barium can also be found. These combine with carbonate ions to form water- insoluble compounds (calcium). Through the total hardness measurement, the potential danger of calcium precipitation is measured as the required carbonate ions form from hydrogen carbonate ions when water heats up or when there are pH values that are greater than 8.2 (comp. Alkalinity). When measuring calcium hardness (SVZ1300 tablet process), only the part of the dissolved calcium in water is measured. The amount of magnesium dissolved in water is determined from the difference between the measurement and the total hardness.
Chlorine (in the form of sodium hypochlorite, calcium hypochlorite, chlorine gas, chlorinated isocyanurates, ...) has prevailed worldwide as the leading disinfectant for swimming and bathing pools. To measure chlorine concentration existing in water under DIN EN 7393, 3 partial values are to be distinguished. 1.) free chlorine: Chlorine that is present as hypochloric acid, hypochlorite ions, or dissolved, elementary, chlorine. 2.) combined chlorine: Portion of total chlorine which is present in the form of chloramines and all chlorinated derivatives of organic nitrogen compounds. 3.) total chlorine: Sum of the other two mentioned forms. While free chlorine immediately creates a disinfection effect, the disinfection potential of combined chlorine is highly limited. Chloramines are responsible for the smell of swimming pools and the irritation of human mucous membranes that lead to red eye. A member of this class of substances is nitrogen chloride which humans already perceive at a concentration of 0.02 mg/l. Free chlorine is measured according to the DPD N° 1 method. Here N,N-diallyl p-phenyl diamine (DPD), an indicator chemical, is oxidized by chlorine and discolors to red. The more intensive the discoloration, the more chlorine is present in the water. Photometric measurements or optical comparison with a colour scale allow the chlorine concentration to be measured. If a DPD N° 3-Tablet is now added to this sample, then the combined chlorine will also be marked. The measured value now corresponds also to the total chlorine concentration. The concentration of combined chlorine corresponds to the difference between total chlorine and free chlorine. Since the slightest traces of the active chemicals in DPD N° 3-tablets lead to combined chlorine becoming active during the measurement, absolute care must be taken prior to the next DPD N° 1-measurement to sufficiently clean the measurement device thus avoiding false readings. The use of two differently calibrated vessels (one generally for measuring free chlorine and the other for measuring total chlorine values) is highly recommended.
Chlorine dioxide (2.33 times heavier than air) is known as a gaseous compound of the halogen, chlorine, and oxygen (ClO2); which has the advantage over pure chlorine that it effects smell and taste perception less and that is also acts as an anti-virus. Chlorine dioxide is also manufactured at special facilities near the production site by combining chlorine gas and/or under-chlorinated acid and a fluid sodium chlorite solution (NaClO2) (10:1). On average 0.05 mg/l – 0.2 mg/l are assumed as average minimum/maximum values.
There can be different reasons for measuring copper values. When it comes to drinking water, copper measurements are made in order to determine the quality of the drinking water. There are no official maximum permissible values for copper in drinking water, but there are recommended values of between 2 to 3 mg/l. Copper is a trace element and is thus essential to human life. A daily consumption of 0.05 – 0.5 mg/kg body weight is considered acceptable. Copper is, however, considered to be dangerous to organisms which is “positively” taken advantage of in swimming pool areas to combat algae and bacteria in the form of copper-containing algicides. However, copper-sulfate containing algicides also have their disadvantages such as the possible discoloration of hair, spotting in swimming suits, and even corrosiveness and copper acetate sedimentation. As an example, copper releases into the drinking water from copper pipes. Pool-i.d. lets you check for copper/ zinc with the Pooltester PT400 or the Comparator …FD400. Here, the “Copper/Zinc LR” tablet simultaneously measures both copper and zinc which is how zinc is eliminated from the reaction through the EDTA tablet included in the set before both individual values are obtained. The “Dechlor” tablet that is also included in the set prevents deviations in the measurement if the residual chlorine content is high.
When using organic chlorine products (trichlorisocyanuric acid and sodium dichlorisocyanurate), the so-called “isocyanuric acid” creates the carrier for chlorine. While the advantage of organic chlorine products clearly lies in the higher portion of active chlorine (up to 90%), the isocyanuric acid carrier substance can limit the speed with which the chlorine can kill off the bacteria when the concentration in water is high (>50 mg/l). It is thus recommended that one measure the cyanuric acid just as regularly as the chlorine content of the pool, in order not to counteract this fact by adding more chlorine (thus leading to higher isocyanuric acid being added). Pool-i.d. offers a Opacity method (SVZ1100), the Comparator Process (…FD1100), and Test Strips (TSL700) to determine the presence of cyanuric acid.
“Pure”, that is distilled water, does not conduct electrical current. Only with the presence of salts dissolved in water, such as sodium chloride, calcium chloride, magnesium chloride, etc. (see also Alkalinity, and Total Hardness), is water able to conduct electrical current. By adding chemicals (disinfectants, pH regulators, algicides, flocculants, etc.), changes in the content of dissolved salts in water also occur, which changes are considered after a certain value (as a rule, max. 2,000 ppm above the level of the water used to fill the pool (tap water)) to be qualitatively poor requiring the water to be changed (fresh water). While an EC meter (e.g. FT33 / FT35) generally measures conductivity (nS/cm or mS/cm), the TDS meter (e.g. FT34 / FT36) calculates the (rough) value of the dissolved salts (all salts) via a conversion formula and displays them in ppm (mg/L) or ppt.
In Northern latitudes, active oxygen is a particularly popular alternative disinfectant to chlorine. Principally, however, - for purposes of measurement – what counts is whether the medium used contains persulfate or peroxide. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 – Method (e.g. Pooltester PT200). When using peroxide containing disinfection media, Hyd. Peroxide tablets are used in connection with the acidifying PT-tablets (e.g. PT300; hydrogen peroxide method). In both cases, the “Active Oxygen (O2)“ designation is in fact misleading. It is not the molecular Oxygen that oxidizes (disinfects); rather it is an Oxygen radical which quite quickly combines with an additional radical to form molecular Oxygen (the air one breaths). This is also the main disadvantage to this method; because the disinfection effect does not last long and the effect is rather limited. As a strict rule, therefore, Chlorine is added in regular intervals when Active Oxygen is used for disinfection. Yet with the DPD N° 4 – Method false readings can then result (when simultaneously using both Chlorine and Active Oxygen), because the potassium iodide contained in this tablet catalytically splits the persulfates and thus the sum of persulfate and chlorine is indicated
In Northern latitudes, active oxygen is a particularly popular alternative disinfectant to chlorine. Principally, however, - for purposes of measurement – what counts is whether the medium used contains persulfate or peroxide. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 – Method (e.g. Pooltester PT200). When using peroxide containing disinfection media, Hyd. Peroxide tablets are used in connection with the acidifying PT-tablets (e.g. PT300; hydrogen peroxide method). In both cases, the “Active Oxygen (O2)“ designation is in fact misleading. It is not the molecular Oxygen that oxidizes (disinfects); rather it is an Oxygen radical which quite quickly combines with an additional radical to form molecular Oxygen (the air one breaths). This is also the main disadvantage to this method; because the disinfection effect does not last long and the effect is rather limited. As a strict rule, therefore, Chlorine is added in regular intervals when Active Oxygen is used for disinfection. Yet with the DPD N° 4 – Method false readings can then result (when simultaneously using both Chlorine and Active Oxygen), because the potassium iodide contained in this tablet catalytically splits the persulfates and thus the sum of persulfate and chlorine is indicated
In Northern latitudes, active oxygen is a particularly popular alternative disinfectant to chlorine. Principally, however, - for purposes of measurement – what counts is whether the medium used contains persulfate or peroxide. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 – Method (e.g. Pooltester PT200). When using peroxide containing disinfection media, Hyd. Peroxide tablets are used in connection with the acidifying PT-tablets (e.g. PT300; hydrogen peroxide method). In both cases, the “Active Oxygen (O2)“ designation is in fact misleading. It is not the molecular Oxygen that oxidizes (disinfects); rather it is an Oxygen radical which quite quickly combines with an additional radical to form molecular Oxygen (the air one breaths). This is also the main disadvantage to this method; because the disinfection effect does not last long and the effect is rather limited. As a strict rule, therefore, Chlorine is added in regular intervals when Active Oxygen is used for disinfection. Yet with the DPD N° 4 – Method false readings can then result (when simultaneously using both Chlorine and Active Oxygen), because the potassium iodide contained in this tablet catalytically splits the persulfates and thus the sum of persulfate and chlorine is indicated
In Northern latitudes, active oxygen is a particularly popular alternative disinfectant to chlorine. Principally, however, - for purposes of measurement – what counts is whether the medium used contains persulfate or peroxide. Water disinfected with persulfate-containing media is measured according to the DPD N° 4 – Method (e.g. Pooltester PT200). When using peroxide containing disinfection media, Hyd. Peroxide tablets are used in connection with the acidifying PT-tablets (e.g. PT300; hydrogen peroxide method). In both cases, the “Active Oxygen (O2)“ designation is in fact misleading. It is not the molecular Oxygen that oxidizes (disinfects); rather it is an Oxygen radical which quite quickly combines with an additional radical to form molecular Oxygen (the air one breaths). This is also the main disadvantage to this method; because the disinfection effect does not last long and the effect is rather limited. As a strict rule, therefore, Chlorine is added in regular intervals when Active Oxygen is used for disinfection. Yet with the DPD N° 4 – Method false readings can then result (when simultaneously using both Chlorine and Active Oxygen), because the potassium iodide contained in this tablet catalytically splits the persulfates and thus the sum of persulfate and chlorine is indicated
Ozone is comprised of 3 oxygen atoms (O3). It is an unstable molecule and disintegrates, after a rather short time either in the air or when it is dissolved in water, into oxygen, O2 and an oxygen radical. The oxidative effect of this oxygen radical is very strong and a depot effect is ruled out because two radicals immediately combine to O2. Ozone is produced directly on the spot by ozone producers and other required appliance-like devices. Special rules and precautions are required, because Ozone is 10 times more poisonous than chlorine. Thus Ozone is only used during a single dosage stretch – outside the pool – and must be filtered out before being used again (activated carbon). The maximum allowable concentration of ozone added to the pool is only 0.05 mg/l which is why ozone is insufficient as a disinfectant requiring it to be supplemented by other – as a rule chlorine content – disinfectants. Ozone kills bacteria, oxidizes organic contamination (e.g. urea), reduces chlorine usage, and leaves no irritating traces behind. As a rule, the human nose which can perceive ozone concentrations of 1:500.000 is the best measuring device. However, ozone combined with chlorine can be measured under the DPD Method. By adding glycine, ozone is eliminated so that chlorine alone can be measured whereby the ozone content is determined from the difference. Pool-i.d offers the Comparator Process (…FD1000) to measure ozone.
Biguanide disinfectants are also gaining in popularity as an alternative to chlorine. Other than with other substitute materials, such as for example ozone or active oxygen, biguanides do not go well with chlorine, bromine, copper, or silver compounds. Nevertheless a counteracting agent is required because biguanides do not deploy an oxidative effect which is required, for example, for the breakdown of organic materials such as ureas and sweat. To do this, as a rule, hydrogen peroxide (H2O2) is used in addition to biguanide which is why Pool-i.d.’s Pooltester PT300 is standardized to measure both values at the same time together with the pH value.
Phosphates come up in nature in multiple ways, for example after it rains in the hills. But detergents also use phosphates as softeners. Phosphates are basically non-poisonous, even encourage the growth of aquatic plants and thus also algae, which are really not welcome in pools. Pool-i.d’s Comparator Method (…FD1200) is designed to test the exact content of phosphates in water. When present in water, phosphates can be removed with “Phosphate Remover” products such as, the “Accepta 9079”.
The pH (potentia Hydrogenii) value is a measure of the strength of the acidic and/or base effect of a watery solution. It is particularly important when preparing bathing water because, among other things, it influences the effectiveness of disinfectants and the compatibility of the water with skin, eyes, and materials. A pH value of 5.5 is ideal for the skin. However, the water would then have so much acid that metallic materials would not only corrode but eyes would start to burn because tears have a pH value of between 7.0 and 7.5. therefore, a compromise must be found. In regard to materials compatibility, the pH value shouldn’t fall below 7.0 in any case. At the same time pH values over 7.6 will have dermatological effects and will also influence the effectiveness of the disinfectant, thus negatively influencing the speed with which bacteria can be killed off. Principally: At pH values above 7.5 = the natural coat of the skin that protects against acids begins to be destroyed (>8.0); in (medium) hard water, calcium precipitation beings (>8.0); the disinfecting effect of chlorine declines with (>7.5) pH values under 7.0 = chloramines form which irritate the mucous membranes and cause irritations to the sense of smell (<7.0); corrosion appearances in metal-content (installed) parts (<6.5); problems with flocculation (<6.2).
(Quaternary Ammonium Compounds) Quaternary Ammonium Compounds are incrementally replacing the copper sulphate content algaecides that have been prevalent to date. They eliminate the disadvantages of copper sulphate content algaecides (see also “copper”). The use of algaecides is necessary despite the proper use of chlorine or other disinfectants because algae populations grow especially when it is humid or after thunder showers.
The Pool-i.d. Test Strip (TSL 600) can be used to measure the salt concentration in sea water pools and/or artificially created saltwater ponds. These are based on using silver nitrate to measure chloride ions. Too high salt water concentrations will corrode built-in swimming pool components. The TSL 600 Test Strip to determine salt (NaCl) content can be used in basins where chlorine is created through an electrolysis system by adding salt (NaCl) directly into the basin water.
(EC Electronic Conductivity) “Pure”, that is distilled water, does not conduct electrical current. Only with the presence of salts dissolved in water, such as sodium chloride, calcium chloride, magnesium chloride, etc. (see also Alkalinity, and Total Hardness), is water able to conduct electrical current. By adding chemicals (disinfectants, pH regulators, algicides, flocculants, etc.), changes in the content of dissolved salts in water also occur, which changes are considered after a certain value (as a rule, max. 2,000 ppm above the level of the water used to fill the pool (tap water)) to be qualitatively poor requiring the water to be changed (fresh water). While an EC meter (e.g. FT33 / FT35) generally measures conductivity (nS/cm or mS/cm), the TDS meter (e.g. FT34 / FT36) calculates the (rough) value of the dissolved salts (all salts) via a conversion formula and displays them in ppm (mg/L) or ppt.
Basically dissolved salts belonging to the alkaline earth elements calcium and magnesium are found in non-distilled water. In rare cases, strontium and barium can also be found. These combine with carbonate ions to form water- insoluble compounds (calcium). Through the total hardness measurement, the potential danger of calcium precipitation is measured as the required carbonate ions form from hydrogen carbonate ions when water heats up or when there are pH values that are greater than 8.2 (comp. Alkalinity). When measuring calcium hardness (SVZ1300 tablet process), only the part of the dissolved calcium in water is measured. The amount of magnesium dissolved in water is determined from the difference between the measurement and the total hardness.
There can be different reasons for measuring copper values. When it comes to drinking water, copper measurements are made in order to determine the quality of the drinking water. There are no official maximum permissible values for copper in drinking water, but there are recommended values of between 2 to 3 mg/l. Copper is a trace element and is thus essential to human life. A daily consumption of 0.05 – 0.5 mg/kg body weight is considered acceptable. Copper is, however, considered to be dangerous to organisms which is “positively” taken advantage of in swimming pool areas to combat algae and bacteria in the form of copper-containing algicides. However, copper-sulfate containing algicides also have their disadvantages such as the possible discoloration of hair, spotting in swimming suits, and even corrosiveness and copper acetate sedimentation. As an example, copper releases into the drinking water from copper pipes. Pool-i.d. lets you check for copper/ zinc with the Pooltester PT400 or the Comparator …FD400. Here, the “Copper/Zinc LR” tablet simultaneously measures both copper and zinc which is how zinc is eliminated from the reaction through the EDTA tablet included in the set before both individual values are obtained. The “Dechlor” tablet that is also included in the set prevents deviations in the measurement if the residual chlorine content is high.