วันอาทิตย์ที่ 16 เมษายน พ.ศ. 2560
ORP(Oxidation Reduction Potental) Theory and Applications.
ORP(Oxidation Reduction Potential)
Similar to the manner in which acidic or alkaline solutions are quantified by pH measurements, solutions can also be graded as oxidizing or reducing based on measurements of ORP(sometimes called "redox").
When an oxidizing and / or reducing agent is dissolved into an aqueous sample, they may react with materials present and produce a voltage, or electromotive force(EMF), that is related to the ratio of oxidized to reduce species in the sample. An electron exchange can develop between this solution and an inert metal sensor immersed in the solution, and the voltage can be measured(When compared to a reference electrode) with a pH/mV meter. This type of measurement is known as redox or ORP. The units of measurement are in mV. At a glance, an ORP electrode may look very similar to a pH electrode. Like a combination pH electrode, both the sensor and the reference are housed in a common body.
The scale of measurement may be positive(indicating oxidizing potential) or negative(indicating reducing). It should be noted that when zero mV is observed, it is really an oxidizing situation because the reference voltage(~200 mV for an Ag/AgCl with KCl electrolyte) is included in the observed mV value in some cases the user may wish to offset the reading to remove the reference contribution. The mV is then said to be approaching the absolute mV scale that references a SHE(standard hydrogen electrode). This type of calibration is called relative mV calibration.
An ORP sensor must be chemically inert ; it cannot be oxidized or reduced itself. It must also have the proper surface characteristics to promote rapid electron exchange, a property known as high exchange current density. Two noble metals have proven to work well for this purpose pure platinum and pure gold are both used in the construction of ORP sensors.
The platinum sensor is often preferred because it is mechanically simpler and safer to produce, Platinum can be welded to glass and has the same thermal coefficient. Sensors made of gold cannot be welded to the glass and are often placed in plastic supports applied to the glass or plastic tube by means of tiny elastomeric bungs. The gold or platinum sensor signal is carried through the electrode body, and together with the reference signal is conducted to the measurement meter via a coaxial cable with BNC connector.
An ORP system does not have a high impedance source(like a pH bulb), but is a potentiometric device that produces a voltage. It also uses similar cables, connectors and calibration solutions. For this reason, a high impedance electronic meter(pH) with many user friendly features are a benefit for this measurement also.
Because of the close relationship between pH and ORP, there is a scale that takes into account the ratio(mV) ORP/pH, the rh scale. The rH range varies from zero to fourty-two, where the extreme values represent the reducing effect of an atmosphere of pure hydrogen(rH=0) and to the oxidizing effect of an atmosphere of pure oxygen(rH=42), respectively.
The formula for obtaining value is as follows.
rH = mV/0.0992(273.15 + T)/(-2 pH)
In this equation, where T is the temperature(degree celcius) of the sample, mV is the ORP(mV) reading, and pH is the pH value of the sample.
The rH scale is not used in the instruments available on the market. A direct mV reading from the electrode is preferred, within the +/- 2000 mV range, without compensation/correlation with the pH/temperature value.
ORP Applications
ORP measurements are based on the potential difference measured between the platinum or gold electrode and a reference electrode. The identical reference system utilized for the pH electrode(Ag/AgCl) is also used for redox measurements. Redox electrodes are used to monitor many chemical processes particularly those involving reversible reactions. Common applications include the following.
Industrial wastewater Treatment
The redox systems used in water treatment are the reduction of chromates and oxidation of cyanides. Waste hexavalent chromium is reduced to trivalent chromium by the addition of sodium bisulfite or sulphur dioxide. In the case of cyanide, chlorine or sodium hypochlorite is used to oxidize the cyanide, followed by the hydrolysis of cyanate to ammonia and carbon dioxide.
Water Sanitation
ORP measurements are being increasingly used as an effective measure of the sanitizing activity in pool, spa and potable water. The kill time of E.coli bacteria in water depends on the ORP value. ORP is a reliable indicator of bacteriological water quality. Water having an ORP value equal to or higher than six hundred and fifty mV are well within accepted sanitization levels for pool and spa waters.
ORP and Sample Preparation Solutions
ORP standard solutions allows users to test the precision of ORP electrodes. For example, by immersing the electrode in ORP solution, reading should fall within the 200 to 275 mV range(@20 degree celcius/ 68 degree farenhite)
วันเสาร์ที่ 15 เมษายน พ.ศ. 2560
The Importance of Soil Testing
Soil is not merely a support system for plants, but a complex world from which the roots obtain water and other required elements. In addition, soil is inhabited by small animals, insects, microorganisms(e.g.fungi and bacteria) which all influence the plant life in one way or another. Soil evolution is a change in its characteristics based upon climate, presence of animals and plants as well as man's action. A natural soil in which evolution is slow, is very different from a cultivated one.
Soil evolution is a change in its characteristics based upon climate, presence of animals and plants as well as man's action. A natural soil, in which evolution is slow, is very different from a cultivated one. Soil is composed of solids(minerals and organic matters), liquids(water and dissolved substances), gases(mostly oxygen and carbon dioxide) and living organisms contains. All these elements provide its physical and chemical properties.
Managing the soil properly is necessary in order to preserve its fertility, obtain better yield and respect the environment. Testing the soil however, is a must in oder to manage it properly. The physical structure of the soil depends on the dimension of the particles of its composition in addition, the particles also differ based on their shape and volumic mass(mass per unit of volume).
Particles classification according to "international Society of Soil Science"(ISSS)
Soil is divided into many classes of texture, according to the percentage of the basic particles(clay, sand and slit). If, for example, we have a soil with thirty-seven percent clay, thirty-eight percent sand and twenty-five percent silt, the soil is classified as "clay loam". Among different types of soil, the loam soil is considered as being suitable for crop growth. However, other types of soil, with a rational management, can also provide positive results.
The soil texture is the cause of important aspects such as porosity, tenacity, adhesivity and plasticity. Porosity is important for the exchange of gases and liquids. Microporosity(porous less than two to ten micrometre) permits water to be retained while macro-pososity(porous more than 10 micrometre) contributes to a fast circulation of air and water. Plants therefore are in need of a correct relationship between micro and macro porosity.
Clay soils have a greater micro-porosity than sandy soils and hence hold more water and remain wet for a longer period. Because of the greater tenacity and adhesivity of clay soils, they are called heavy, while sandy soils are referred to as light.
Organic matter, caused by animal and vegetable residues, is another important constituent of the solid part of the soil. Organic matter has a positive effect on the soil fertility by adding nutrients, stabilizing the pH reaction and permitting a good retainment of water. Organic matter is also important for the activity of microorganisms and in general, contributes towards prevention of soil erosion. The collioidal portion, composed of micro-particles(one to one hundred micrometre), is important for holding nutrients. Since most of these particles have a negative charge, the colloidal portion has a particularly large capacity to retain cations(ammonium ion, potassium ion, sodium ion, calcium ion, magnesium ion, etc.). The CEC(Cation Exchange Capacity) is higher in soils rich with clay and organic matter than in sandy soils.
Soil pH can be acid, neutral, or alkaline. Each plant has a range of pH in which it thrives and most plants prefer conditions near the neutral mark(pH 5.5 - 7.5). There are however plants that prefer acid or alkaline environments. The solubility of the nutrients, that is the ability of the plants to absorb them, depends largely on their pH value. The soil microbiological activity is also pH dependent. Most bacteria, specially those putting nutrients at the plants disposition, prefer moderately acid of slightly alkaline conditions. The pH level hence influences the fertility of the soil.
Fruit and Vegetable : Testing the nitrogen and phosphorus level in your soil is important, especially before seeding and replanting. While root vegetables need phosphorus, leafy plants require more Nitrogen. Potassium however, helps increase the quality of the crop. With the Hanna Quick Soiltest, growers able to keep these three important elements under control.
Flowers and Shrubs : The right quantity of potassium is the key factor in ensuring beautiful and fragrant flowers. The other elements play an important role too in achieving quick and harmonious growth.
Lawns : A lush lawn is the result of care and attention. In addition to tilling and irrigation, the pH and nitrogen levels need regular checks.
Fruit and Decorative Trees : Trees are the most appealing feature of our gardens.Nitrogen and phosphorus help in speeding up the growth of young plants, encouraging abundance of foliage and strengthening the trunk and the roots. Potassium, on the other hand keeps, the plants in tip top condition by protecting them from disease.
Bonsai and Houseplants : Every time a houseplant, but in particular a bonsai is potted, the choice of soil mixture is of prime importance. Having prepared the mixture, The Hanna Quick Soiltest will in a matter of minutes test the level of pH and other elements ensuring a livelier plant.
The chemical composition of soil includes pH and chemical elements. Soil analysis is necessary for better management of fertilization and to know the residues of fertilization and to know the residues of fertilizers in relation to the crop, tillage and the most suitable plant choice for soil composition. An analysis can highlight shortages and help the understanding of the causes of an abnormal growth. By using the Hanna soiltest, it is possible to measure pH and the most important elements for plant growth, that is, nitrogen(N), phosphorus(P) and potassium(K).
Testing the soil during each crop cycle and comparing the results with plant growth can be a useful experiment for subsequent cultivations.
In agricultural applications, monitoring the quality of the soil is extremely important for the health and growth of crops. The pH level is an excellent guide as to which plants may thrive in a particular terrain, as well as indicating which conditioners and fertilizers to use, Hanna combination test kits allow you to test not only for pH, but for nitrogen, phosphorous and potassium which are all important for the quality of soil as well
Soil evolution is a change in its characteristics based upon climate, presence of animals and plants as well as man's action. A natural soil, in which evolution is slow, is very different from a cultivated one. Soil is composed of solids(minerals and organic matters), liquids(water and dissolved substances), gases(mostly oxygen and carbon dioxide) and living organisms contains. All these elements provide its physical and chemical properties.
Managing the soil properly is necessary in order to preserve its fertility, obtain better yield and respect the environment. Testing the soil however, is a must in oder to manage it properly. The physical structure of the soil depends on the dimension of the particles of its composition in addition, the particles also differ based on their shape and volumic mass(mass per unit of volume).
Particles classification according to "international Society of Soil Science"(ISSS)
Soil is divided into many classes of texture, according to the percentage of the basic particles(clay, sand and slit). If, for example, we have a soil with thirty-seven percent clay, thirty-eight percent sand and twenty-five percent silt, the soil is classified as "clay loam". Among different types of soil, the loam soil is considered as being suitable for crop growth. However, other types of soil, with a rational management, can also provide positive results.
The soil texture is the cause of important aspects such as porosity, tenacity, adhesivity and plasticity. Porosity is important for the exchange of gases and liquids. Microporosity(porous less than two to ten micrometre) permits water to be retained while macro-pososity(porous more than 10 micrometre) contributes to a fast circulation of air and water. Plants therefore are in need of a correct relationship between micro and macro porosity.
Clay soils have a greater micro-porosity than sandy soils and hence hold more water and remain wet for a longer period. Because of the greater tenacity and adhesivity of clay soils, they are called heavy, while sandy soils are referred to as light.
Organic matter, caused by animal and vegetable residues, is another important constituent of the solid part of the soil. Organic matter has a positive effect on the soil fertility by adding nutrients, stabilizing the pH reaction and permitting a good retainment of water. Organic matter is also important for the activity of microorganisms and in general, contributes towards prevention of soil erosion. The collioidal portion, composed of micro-particles(one to one hundred micrometre), is important for holding nutrients. Since most of these particles have a negative charge, the colloidal portion has a particularly large capacity to retain cations(ammonium ion, potassium ion, sodium ion, calcium ion, magnesium ion, etc.). The CEC(Cation Exchange Capacity) is higher in soils rich with clay and organic matter than in sandy soils.
Soil pH can be acid, neutral, or alkaline. Each plant has a range of pH in which it thrives and most plants prefer conditions near the neutral mark(pH 5.5 - 7.5). There are however plants that prefer acid or alkaline environments. The solubility of the nutrients, that is the ability of the plants to absorb them, depends largely on their pH value. The soil microbiological activity is also pH dependent. Most bacteria, specially those putting nutrients at the plants disposition, prefer moderately acid of slightly alkaline conditions. The pH level hence influences the fertility of the soil.
Fruit and Vegetable : Testing the nitrogen and phosphorus level in your soil is important, especially before seeding and replanting. While root vegetables need phosphorus, leafy plants require more Nitrogen. Potassium however, helps increase the quality of the crop. With the Hanna Quick Soiltest, growers able to keep these three important elements under control.
Flowers and Shrubs : The right quantity of potassium is the key factor in ensuring beautiful and fragrant flowers. The other elements play an important role too in achieving quick and harmonious growth.
Lawns : A lush lawn is the result of care and attention. In addition to tilling and irrigation, the pH and nitrogen levels need regular checks.
Fruit and Decorative Trees : Trees are the most appealing feature of our gardens.Nitrogen and phosphorus help in speeding up the growth of young plants, encouraging abundance of foliage and strengthening the trunk and the roots. Potassium, on the other hand keeps, the plants in tip top condition by protecting them from disease.
Bonsai and Houseplants : Every time a houseplant, but in particular a bonsai is potted, the choice of soil mixture is of prime importance. Having prepared the mixture, The Hanna Quick Soiltest will in a matter of minutes test the level of pH and other elements ensuring a livelier plant.
The chemical composition of soil includes pH and chemical elements. Soil analysis is necessary for better management of fertilization and to know the residues of fertilization and to know the residues of fertilizers in relation to the crop, tillage and the most suitable plant choice for soil composition. An analysis can highlight shortages and help the understanding of the causes of an abnormal growth. By using the Hanna soiltest, it is possible to measure pH and the most important elements for plant growth, that is, nitrogen(N), phosphorus(P) and potassium(K).
Testing the soil during each crop cycle and comparing the results with plant growth can be a useful experiment for subsequent cultivations.
In agricultural applications, monitoring the quality of the soil is extremely important for the health and growth of crops. The pH level is an excellent guide as to which plants may thrive in a particular terrain, as well as indicating which conditioners and fertilizers to use, Hanna combination test kits allow you to test not only for pH, but for nitrogen, phosphorous and potassium which are all important for the quality of soil as well
Hanna Instruments HI3896 Professional Agriculture Test Kit for 25 Tests
Soil Savvy - Soil Test Kit
วันศุกร์ที่ 14 เมษายน พ.ศ. 2560
Acidity Olive oil tester
Acidity Olive oil tester
Acidity, defined as percent oleic acid, is a parameter that
indicates olive oil freshness. A high acidity value indicates the oil quality
has diminished and is at risk of becoming rancid. Acidity is used to
discriminate an extra virgin olive oil from all other olive oils. According to
the CEE 2568/91 regulation, olive oil is considered extra virgin when its
acidity level is below one percent. A low acidity value also indicates a
natural extraction process occurred soon after olive harvesting.
Acidity(expressed as percent oleic acid) is the most fundamental
measurement of olive oil. It is the primary indicator of olive oil purity and
freshness. The quanlity of olive oil is directly related to the degree of
breakdown of the fatty acids in the oil. As
the bound fatty acids break down, free fatty acids are formed which
increase the acidity of the percent oil. Acidity, expressed as oleic acid, is a
measure of the free fatty acid present in the oil, which is directly related to
its purity.
The
quanlity of olive oil can be adversely affected during maturation or by
environm ental conditions. Mishanding, processing and bruishing during
harvesting can also contribute to a breakdown of fatty acids and an increase in
free acidity. Improper and / or long term storage can cause olive oil to
breakdown and become rancid. Regular acidity testing is the best way to ensure
and maintain quality and freshness.
Normally, testing acidity is a complicated
process requiring the use of various chemicals in a laboratory environment.
Studies have shown that the quality of olive oil has a direct impact on its
health benefits. Extra Virgin Olive Oil contains higher levels of antioxidants,
particularly phenols and vitamin E (because it is less processed). Antioxidants
can help prevent oxidation damage to body tissue caused by free radicals,
Studies have also shown that the oxidation of LDL (or bad) Cholesterol is associated
with the hardening of arteries that can lead to heart disease. With some test
kit, it is possible to easily and accurately test the quality of olive oil at
various stages of processing and storage to monitor and maintain the highest
quality.
In accordance with the European Community(EC) reg. CEE2568/91 quality classification of olive oil based on acidity(expressed as percent oleic acid) is as follows :
Extra Virgin Olive Oil : Acidity</= 1% "Perfect flavor and odor", with a maximum acidity, expresses as oleic acid of 1 g/100 g.
Virgin Olive Oil : Acidity 1 - 2 % "Perfect flavor and odor", with a maximum acidity, expresses as oleic acid, of 2g/100 g.
Ordinary Virgin Olive Oil : Acidity 2 - 3 .3%(tolerance of 10 %) "Good flavor and odor", with a maximum acidity, expressed as oleic acid, of 3.3g/100 g.
Virgin Lampante Olive Oil : +3.3 %. Not fit for human consumption "Off flavor and odor", with a maximum acidity, expresses as oleic acid, > 3.3g/100 g.
In accordance with the European Community(EC) reg. CEE2568/91 quality classification of olive oil based on acidity(expressed as percent oleic acid) is as follows :
Extra Virgin Olive Oil : Acidity</= 1% "Perfect flavor and odor", with a maximum acidity, expresses as oleic acid of 1 g/100 g.
Virgin Olive Oil : Acidity 1 - 2 % "Perfect flavor and odor", with a maximum acidity, expresses as oleic acid, of 2g/100 g.
Ordinary Virgin Olive Oil : Acidity 2 - 3 .3%(tolerance of 10 %) "Good flavor and odor", with a maximum acidity, expressed as oleic acid, of 3.3g/100 g.
Virgin Lampante Olive Oil : +3.3 %. Not fit for human consumption "Off flavor and odor", with a maximum acidity, expresses as oleic acid, > 3.3g/100 g.
Today our water supplies are becoming more contaminated with
corrosive chemicals from industrial dumping or acid rain. Therefore, acidity
measurements are an essential monitoring device to define and control pollution
in sewers, lakes and rivers. Acidity of water is equally important to monitor
in soils and fish farming to maximize the growing environment.
The acidity of a
water sample is its capacity to neutralize hydroxide ions. Acidity may be
caused by mineral acids such as sulfuric acid or hydrochloric acid or by
dissolved carbon dioxide. Most commonly in drinking water. Carbon dioxide is
the principal cause of acidity in drinking water, but also it can be caused by
mineral and organic acids. Acidity increase the corrosive behavior of water.
Drinking water with high acidity level is likely to be corrosive to copper
water pipes and to the solder which joins those pipes.
High levels of copper
and lead indrinking water often occur when acidic water stands in pipes for
extended periods of time(such as over night). In addition to creating a
possible health hazard due to dissolved metal ions, acidity in water can cause
copper plumbing to develop pin hole leaks after a few years.
With the use of diluted sodium hydroxide as the titrant and
bromphenol blue or phenolphthalein indicators, the contribution of strong or
organic acids can be determined. The measurement of the strong acid
contribution to the sample acidity is known as methyl orange acidity. This is
carried out by titrating with sodium hydroxide until the solution turns from
yellow to green/blue(pH endpoint about 4.5). The total acidity caused by both
mineral and organic acids is determined by titrating to an endpoint pH of 8.3,
using phenolphthalein as an indicator. This is known as phenolphthalein inacidity.
The total
exchangeable acidity(TEA) is a measure of the amout of acidic cations(hydrogen,
aluminum, iron and manganese) present is soil. It is expressed in
milliequivalent per one hundred grams(meq/100 g) of soil. The more acidic it is
a soil, the lower the soil pH value will be Soils in humid regions normally
accumulate increasing amounts of exchangeable acidity as they get older. Soil
acidity may develop toxicity that can damage or kill plants. The extraction
method is the potassium chloride method. The acidic cations are firstly leached
from the soil and then titrated with a standard alkali. The reaction endpoint
is visually indicated by a color change(from colorless to pink) of the
indicator reagent.
วันพฤหัสบดีที่ 13 เมษายน พ.ศ. 2560
วันพุธที่ 12 เมษายน พ.ศ. 2560
The Important of Pool and Spa Water Testing
The Significance of Pool and Spa Water Testing
Residual
Disinfection and pH Control
In terms of
swimming pool treatment, disinfection or sanitizing basically means to rid the
pool of bather pollution, destroy bacteria, and control nuisance organisms like
algae, which may occur in the pool, filtration equipment and piping. There are
a number of techniques used, namely, chlorine, bromine and ozone dosing
systems, of which chlorine is the most common.
Chlorine
Chlorine is a
strong oxidizing agent that destroys organic pollutants and bacteria. Chlorine
combines with compounds containing nitrogen to form chloramines, during which
only part of the chlorine will be used while the rest remains active, continuing
it’s disinfecting action.
Combined
chlorine is the quatity of chlorine that has already combined with nitrogen
containing compounds, it is much less effective as a disinfectant than free
chlorine, which has yet to make the transition. The addition of combined
chlorine, and free chlorine gives total chlorine. A pool manager needs to aim
for the perfect balance where free and total chlorine are proportionally equal,
and thus to keep the combined chlorine level near zero. The presence of
chloramines is undesirable because of the distinctive “swimming pool smell” as
well as irritation to the eyes and mucous membranes caused by combined
chlorines like dischloramines.
Commercial chlorine for disinfection may
be available as a gas(Cl2), a liquid like sodium hypochlorite or
bleach(NaOCl) or in a solid state like calcium hypochlorite, Chlorohydantoins
or chlorocyanuric acid compounds. These compounds, once dissolved in water,
establish equilibrium between the hypochlorous acid(HOCl) and the hypochlorite
ions(OCl-). Although both forms and considered free chlorine, it is
the hypochlorous acid that provides the strongest disinfecting and oxidizing
characteristic of chlorine solutions. The amount of hypochlorous acid in
chlorinated water depends upon the pH value of the solution, Changes in pH
value will effect the HOCl equilibrium in relation to the hydrogen and
hypochlorite ions.
As
depicted by the graph, HOCl decrease and OCl- increases as pH
increase. At a low pH, almost all the free chlorine is in the molecular form
HOCl, and atpH of around seven point five, the ratio between HOCl and OCl-
is 50 : 50. Since the ionic form OCl- is a slow acting
sanitizer while the molecular HOCl is a fast acting, it is important to measure
pH regularly. As a general rule a pH of about seven point two is recommended to
maintain fast acting disinfection conditions.
Bromine
In many countries
bromine sanitizing has been introduced as an alternative for chlorine, although
it is not as strong. The advantage of bromine lies in its stability at higher
temperatures(advantageous for heated pools and hot tubs), and its maintained
disinfection power at a higher pH. Futhermore, there is very little reaction
between bromine and nitrogen compounds, reducing the unpleasant odor, and eye
irritation problems. The main disadvantage of bromine is the slower acting
disinfecting power, making it less suitable for larger pools.
Ozone
Ozone is a very
strong oxidizing agent that destroys organic compounds that are especially
difficult to oxidize. It allows the pool manager to very efficiently remove
combined chlorine without frequently refreshing large amounts of pool water. By
the time the water passes through the filter units, ozone has already completed
sanitizing and it is not effected by the pH level.
Mainly
because of its strong oxidizing power, the return water may contain trace
concentrations of ozone. It imperative to know that ozone is very unstable, so
to ensure thorough sanitization of the water, low – level chlorination remains
necessary.
The water Balance and Langelier Index
Pool water
Characteristics need to be maintained in a balanced state to avoid numerous
issues. Measuring certain variables is extremely important to predict of the
water is corrosive, scalling or balanced. A saturation index developed by Dr.
Willfred Langelier is widely used to predict the balance of swimming pool
waters. It represents the estimation of a solutions ability to dissolve or
precipitate calcium carbonate deposits. A certain level of this
precipitation(filming) is desired to insulate pipes and boilers from contact
with water. When no protective filming is formed, water is considered to be
corrosive. On the other hand, too much filming can develop into scaling and incrustation
of the pipes.
In the
treatment and monitoring of pool water, the pool manager must ensure that
related parameters such as alkalinity, hardness and pH and dutily taken into
consideration.
The Langelier Index is a powerful tool to calculate the water
balance, and to predict corrosion or scaling problems. Theoretically, a LI of zero indicates perfect water condition for swimming pools. If LI > 0, scaling and staining of the water is present, and if LI < 0 the water is corrosive and highly irritating, A tolerance of +/- 0.4 is normally acceptable.
The Langelier formula is expressed as :
LI = pH + TF + HF + AF - 12.5
Where :
LI = Langelier Index(also called Saturation Index)
pH = pH of the water
TF = temperature factor.
HF = hardness factor, log(Ca hardness, ppm as calcium carbonate)
AF = alkalinity factor, log(alkalinity, ppm as calcium carbonate)
To calculate the exact Langelier Index of your water please use the water Index reference tables.
For most pools, water is balanced if :
** The pH value is maintained within the recommended ranges of pH 7.2 - 7.6
** Ideally the Alkalinity should be maintained within a range of 80 - 125 ppm.
** The Calcium Hardness should be maintained within a range of 200 - 400 ppm.
To calculate your water balance, three parameters must be measured, calcium hardness, alkalinity and pH. Find the hardness and alkalinity factor in the Water Index reference tables below. The water temperature is, in general, maintained between 24 degree celcius and 34 degree celcius. Assuming the temperature is kept within those ranges, an average value or 0.7 may be used.
Water Balance = pH+TF+HF+AF
The Langelier Index is a powerful tool to calculate the water
balance, and to predict corrosion or scaling problems. Theoretically, a LI of zero indicates perfect water condition for swimming pools. If LI > 0, scaling and staining of the water is present, and if LI < 0 the water is corrosive and highly irritating, A tolerance of +/- 0.4 is normally acceptable.
The Langelier formula is expressed as :
LI = pH + TF + HF + AF - 12.5
Where :
LI = Langelier Index(also called Saturation Index)
pH = pH of the water
TF = temperature factor.
HF = hardness factor, log(Ca hardness, ppm as calcium carbonate)
AF = alkalinity factor, log(alkalinity, ppm as calcium carbonate)
To calculate the exact Langelier Index of your water please use the water Index reference tables.
For most pools, water is balanced if :
** The pH value is maintained within the recommended ranges of pH 7.2 - 7.6
** Ideally the Alkalinity should be maintained within a range of 80 - 125 ppm.
** The Calcium Hardness should be maintained within a range of 200 - 400 ppm.
To calculate your water balance, three parameters must be measured, calcium hardness, alkalinity and pH. Find the hardness and alkalinity factor in the Water Index reference tables below. The water temperature is, in general, maintained between 24 degree celcius and 34 degree celcius. Assuming the temperature is kept within those ranges, an average value or 0.7 may be used.
Water Balance = pH+TF+HF+AF
Calcium
The presence
of calcium in the system is desired to ensure filming on those places where the
temperature is relatively high, like in boilers and pipes transporting warm
water. Scaling must be avoided because it reduces heat transfer and pump
capacity, and causes cloudiness in the water. It is recommended to maintain the
calcium hardness value within the range from two hundred to four hundred as
calcium carbonate(CaCO3).
Alkalinity
Alkalinity
is the measure of the total concentration of alkaline substances, mostly
bicarbonates, dissolved in the water. The higher the alkalinity, the more
resistant the water is to pH change. At the same time, high alkaline water is a
major contributor to scaling problems like incrustation in filtration
equipment, pumps, and piping.
pH
It is recommended to
maintain the alkalinity value within the range from eighty to one hundred and
twenty-five part per million as calcium carbonate(CaCO3)
The pH of the
water is an important factor since at lower pH levels the corrosion rate
increase. If the alkalinity values are sufficiently high, it will not be
difficult to control the pH. Most pool managers prefer to keep the pH between seven point two and seven point four to best maintain low corrosion rates and a sufficient activity of
chlorine.
Around the world, swimming pool and spa facilities welcome dozens, even hundreds of people on a daily basis. A basic necessity of pool water treatment is to maintain the water in a safe and plesant condition for the bathers. In order to achieve ideal water conditions, swimming pool water requires testing on a daily and sometimes hourly basis for disinfection of residuals and maintaining pH levels. Equally important, calcium hardness and alkalinity levels should be monitored weekly to ensure the pool water is well balanced, thus to avoid corrosion and scale formation.
Around the world, swimming pool and spa facilities welcome dozens, even hundreds of people on a daily basis. A basic necessity of pool water treatment is to maintain the water in a safe and plesant condition for the bathers. In order to achieve ideal water conditions, swimming pool water requires testing on a daily and sometimes hourly basis for disinfection of residuals and maintaining pH levels. Equally important, calcium hardness and alkalinity levels should be monitored weekly to ensure the pool water is well balanced, thus to avoid corrosion and scale formation.
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