The Langelier Saturation index LSI is an equilibrium model derived from the theoretical concept of saturation and provides an indicator of the degree of saturation of water with respect to calcium carbonate.
Langelier Saturation Index (LSI)
It can be shown that the Langelier saturation index LSI approximates the base 10 logarithm of the calcite saturation level. The Langelier saturation level approaches the concept of saturation using pH as a main variable. The LSI can be interpreted as the pH change required to bring water to equilibrium.
Water with a Langelier saturation index of 1. Reducing the pH by 1 unit will bring the water into equilibrium. This occurs because the portion of total alkalinity present as CO 3 2- decreases as the pH decreases, according to the equilibria describing the dissociation of carbonic acid :. If LSI is close to zero: Borderline scale potential. Water quality or changes in temperature, or evaporation could change the index.
The LSI is probably the most widely used indicator of cooling water scale potential. It is purely an equilibrium index and deals only with the thermodynamic driving force for calcium carbonate scale formation and growth. It provides no indication of how much scale or calcium carbonate will actually precipitate to bring water to equilibrium.
It simply indicates the driving force for scale formation and growth in terms of pH as a master variable. LSI is defined as:. Click here to see an example of a Langelier Index calculation. However, there is some controversy concerning the correlation of these indices, and particularly the LSI, with the corrosivity of waters.
While some sectors of the water management industry squarely use the indices as a measure of the corrosivity of their waters, more alert specialists, including our dear friends Paul Dillon and Bert Krisher, are very cautious as to how far one can extrapolate the indices to such usage.
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Langelier Saturation Index LSI The Langelier Saturation index LSI is an equilibrium model derived from the theoretical concept of saturation and provides an indicator of the degree of saturation of water with respect to calcium carbonate.Langelier Saturation Index, or commonly Langelier, or LSI, is based on the investigation of the carbonate equilibrium in water, to assess the true pH or true hardness of water.
More simply, it is a calculation method based on certain water testing parameters that give a more accurate or true investigation as to the corrosivity index or corrosion potential or water aggressiveness or true pH, on one hand, or on the other hand the scaling index, or hardness potential or true hardness, rather than just basic water test figures which may not reveal the full picture of how the water is behaving. Water is an effective solvent and picks up impurities easily. Pure water is defined as tasteless, colourless and odourless, with a neutral pH of 7 and is often called the universal solvent.
Dissolved solids refer to any minerals, salts, metals, cations or anions dissolved in water. Total dissolved solids or TDS, include inorganic salts mainly calcium, magnesium, potassium, sodium, bicarbonates, chlorides and sulfates and some small amounts of organic matter that are dissolved in water. Corrosivity is a measure of how aggressive water is, for example when corroding pipes and fittings.
Corrosive water can leach iron, lead, copper, etc. Corrosion in general is a complex interaction between water and metal surfaces and materials in which the water is stored or transported. With regards to the corrosion potential of your own drinking water, the main concerns are the presence of toxic metals, such as lead and copper and having a bitter or metallic taste in the water, and in relation to the use of corrosive domestic household water through the general plumbing system, the concerns are for pipework, tanks, fittings and bathroom sanitary ware, and with the aesthetic problems of stained laundry and greenish blue stains around basins and drains.
When a household is plumbed using a high level of copper pipework grade of copper important and either aggressive langelier usually less than Water hardness or the balanced process of water softening by ion exchange plays no real part in exceptional langelier swings, or copper deposition. Copper deposition in feed water and heating systems may also become noticeably aggravated around seasonal weather shifts say from summer to autumn, august to september when heating systems are turned on more regularly and the weather becomes cold.
The simplest water test done in seconds is with a copper test strip or more accurately water measured in the laboratory for copper, something you probably may be aware of by the visibility of greenish blue staining.
Some of the factors that increase the corrosive potential of water are :. As it can be seen from the table above, hard water that acts hard by producing clearly visible limescale deposits in a short period of time, say in the higher cases found on water schemes and in wells in the West of Ireland at around ppm of hardness, may in fact act a little differently from scheme to scheme and well to well, if the LSI value varies widely. A water test report showing ppm to ppm of total hardness with expectations of highly problematic scaling, but with a balanced or mildly scaling Langelier Saturation Index, may show little or less concern during the daily household bathing, washing and cleaning chores on some rare schemes, however those schemes usually with ppm to ppm of total hardness will most likely have higher Langelier Saturation Index values and exhibit a much higher tendency for scaling and the subsequent signs of limescale formation throughout the plumbing system.
A common mistake made when guessing the cause of blonde hair turning green is chlorine in water or in swimming pools or after certain hair treatments, although excessive hair bleaching can increase hair damage and porosity and exposure to absorption of water borne metals.
The real cause is usually copper levels in water leaching from copper pipes, often in larger houses with a lot of copper pipework. The level of copper in water that can turn hair green can be as low as 0.
Langelier Saturation Index Calculator
The cause of copper leaching from copper pipework is extensively described above, and although water testing may show pH levels as high as 8 pH and Langelier at a reasonable balance at the point of showering and bathing with minimal levels of copper, still if hair turns green then there is going to be some level of copper deposition in the water and it does not help if there is long term hair damage through bleaching where copper oxides coalesce with proteins in the hair.
By altering the balance of buffering agents in the water such as alkalinity and hardness to a measured level without over-hardeneing water, and using the correct water treatment even after softened wateran increase in pH and Langelier will help to eradicate copper leaching however minimal or at higher levels.
The use of "chelating" hair shampoos after corrective water treatment once water is re-buffered and copper levels disappear, will rapidly sequester green colouring from blonde hair within a week or so. A much rarer condition is orange hair from iron in water, which requires a different type of water treatment employing backwashable iron removal systems. Welcome to our new look website for Galway Water, a new responsive site designed to work on a range of viewing platforms, mobile, tablet and desk top.Most pool owners will carry out a regular check on the key pool water factors such as pH, Total Alkalinity, Chlorine levels and Calcium Hardness.
However these do not provide the complete picture as to what is happening in your pool and often a more comprehensive understanding is needed.
However there may be issues with dissolved minerals in the water, cloudy water, white powdery material on pool surface along with corrosion of surfaces and equipment. Left undetected these can result in expensive upgrades. The Langelier or Saturation Index for pools will identify these issues beforehand and can save you considerable expense and pain.
The concern with water saturation results from the aggressive nature of dissolved minerals in water — particularly Calcium Carbonate — which can lead to scaling or etching of plaster and metallic equipment. It is a relatively new concept for pool and spa professionals and deserves to be thoroughly understood. In the past, water saturation was left to hazard and the results were that some pools would last forever while others would need constant repairs.
The Langelier or Saturation Index is a calculation used to determine the adequacy of the pool or spa water chemistry, as it relates to corrosion and scale-formation. The adjustment of the pH, total alkalinity or calcium hardness can be used to adjust the Langelier Index, so that it falls within the ideal range. Corrosive water conditions are more likely to cause irritation and sensitivity to chlorine.
Scale-forming tendencies are more likely to be associated with cloudy water problems and a loss of chlorine efficiency. At a given temperature, swimming pool water chemistry must be balanced by adjusting pH, alkalinity, and calcium hardness in order to maintain the proper saturation with respect to calcium carbonate to avoid corrosion of metallic surfaces, etching of tile grout and plaster, scaling, and cloudy water.
This test will tell you whether your water is too acidic, too basic or just right. Water that is too basic or too acidic can ruin your pool.
Luckily, testing the saturation index is a simple process. If not sure please contact your favourite pool shop, or Hitchins Technologies Pty Ltd info poolpaint. If you like what you see and want to talk to us about EPOTEC, its performance and costs involved for your project please fill out the form. Do it yourself. Join many other Australians who have found the ideal way to economically rejuvenate their pool with a proven, hard wearing, easy clean, decorative and long lasting paint finish.
It is calculated 58 KB using the pH, alkalinity, calcium concentration, total dissolved solids, and water temperature of a water sample collected at the tap.
If the. The Langelier Index is one of several tools used by water operators for stabilizing water to control both internal corrosion and the deposition of scale. Water supply operators can optimize their water supply systems and identify leakage potentials with the Langelier Index.
Leakage is a common problem in Newfoundland and Labrador due to the acidic nature of provincial natural waters. Langelier Index values outside this range may result in laundry stains or leaks. Using the Community Water Resources Reports feature a Community can be selected to generate reports that show all of the Drinking Water Quality data the Department has collected for that community.
If the; Langelier Index is negative, then the water is under saturated with calcium carbonate and will tend to be corrosive in the distribution system Langelier Index is positive, then the water is over saturated with calcium carbonate and will tend to deposit calcium carbonate forming scales in the distribution system If Langelier Index is close to zero, then the water is just saturated with calcium carbonate and will neither be strongly corrosive or scale forming.Leave us a question or comment on Facebook.
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If the water is corrosive, the water will try to saturate itself by dissolving the surface composition structure of your pool. If it is scale forming it will try to correct its over saturation by precipitating the hard water salts causing cloudy water and eventually deposit scale on pool components. Suggested water temperature is between 27 and Optimum range 7. If the result of this calculation is zero, the target goal, then the water is balanced.
If the answer is less than 0, the water leans toward being corrosive. If it is greater than 0, then it is indicative of scale forming. An acceptable range is If the result is outside this range, adjustments should be made to the hardness, alkalinity and pH to bring it as close to zero as possible and ideally within the optimum ranges shown above.
Be aware however, that while the water may be balanced from a corrosion and scaling point of view it does not necessarily mean that it is ideal for chemical efficiency and bather comfort.
Select Value 5 ppm 25 ppm 50 ppm 75 ppm ppm ppm ppm ppm ppm ppm ppm ppm ppm. Search or Browse Our Site.This calculator helps you determine the scaling potential of the water by using the Langelier Saturation Index.
For an explanation of the formula click here. Explanation of the Langelier Saturation formula. Other calculators Warning: Lenntech BV cannot be held responsible for errors in the calculation, the program itself or the explanation. For questions or remarks please contact us. Temperature Unit Conversion. Pressure Conversion Program and ideal gas law.
Dynamic Viscosity Program. Kinematic Viscosity Calculator.
Langelier Saturation Index(LSI) Calculation
Give the values of your water analysis. Table 1: Input table pH. If you do not have a water analysis you can use the values in table 2.
The Langelier Saturation Index formula is For an explanation of the formula click here. Water is undersaturated with respect to calcium carbonate. Undersaturated water has a tendency to remove existing calcium carbonate protective coatings in pipelines and equipment.
Enter the water test readings as indicated and click the "Calculate" button. If the resulting LSI displayed is lower than By entering different values for each water condition level into the calculator you can determine what combination of water condition levels will provide balanced water in your pool and which are suitable for your pool operating requirements.
LSI provides a "snap-shot" assessment of pool water balance. Water balance conditions in a pool will change naturally all the time. LSI should be maintained in the range LSI can be increased by taking any one or more of the following actions:.
Pool Water Testing Results. Select Value 5 ppm 25 ppm 50 ppm 75 ppm ppm ppm ppm ppm ppm ppm ppm. Select Value 0 ppm 5 ppm 25 ppm 50 ppm 75 ppm ppm ppm. PristineBlue Sanitation System. Vinyl Pool Liner: - ppm. Tiled Pool: - ppm.