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Thread: Langelier and Calcite Saturation Indices (LSI and CSI)

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    Langelier and Calcite Saturation Indices (LSI and CSI)

    Since the issue of the applicability of the LSI or CSI keeps coming up, I'm copying much of the following from the JSPSI. I'm in the camp with Wojtowicz and his Part 6 has the same arguments that I've made (I read this stuff afterwards so I came to the same conclusions independently). Part of the problem is that the original LSI was modified (by someone unknown) for the pool industry. Whenever you see log terms for TDS and temperature dependence, these are approximations and not based the original thermodynamics (and yes, the Wojtowicz revision to the index has a log term for TDS).

    These indices do nothing more than predict saturation of the water with calcium carbonate. If the water is over-saturated, then there is the possibility of scale, but the index does not determine its rate nor if there are seed crystals to get such precipitation or scaling started. Likewise, if the water is under-saturated, then there is the possibility of dissolving of plaster, but again the rate is not determined and technically it is only the dissolving of calcium carbonate itself that would be possible (I talk about other components of plaster in this thread). These indices do not predict metal corrosion whatsoever. When one refers to water being "corrosive" in terms of these indices, it is only in reference to the dissolving of calcium carbonate as a component of plaster (plaster is mostly calcium oxide in a hydrated silicate).

    I'd like to get a copy of the first source below. I just recently ordered a book with all of the Wojtowicz articles he wrote for JSPSI.

    Sources relating to the inapplicability of the LSI are here:

    Cardall, John T. and Jonathan S. Powell Jr. “The Fallibility of the Langelier Index.” Pool News (4 Aug. 1974): 40–43. [Cardall and Powell discuss the inappropriateness of applying the Langelier Index to swimming pools, and describe experiments which they conducted, refuting the validity of the index in the pool environment. They discuss some of the factors in the pool environment which interfere with the index.]

    Hamilton, Jock qtd. in Paul Konrad. “Whose Numbers Tell the Story?” Pool and Spa News (10 Apr. 1989): 22–26. [Hamilton is quoted in this story as refuting the Langelier Index’s appropriateness in swimming pools, and offering an alternate index (the Hamilton Index) which he claims sufficiently addresses the pool environment.]

    Langelier, Wilfred F. “The Analytical Control of Anti–corrosion Water Treatment.” Journal of the American Water Works Association (AWWA) v28 #10 (1936):1500–1521. [This is the original paper published on the saturation concept, which has since become known as the Langelier Saturation Index. Langelier is cited as an associate professor of sanitary engineering at UC Berkeley. The article contains formulas, tables, photographs, and references, as well as a history of study on saturation. The index is applied to municipal water piping systems. No mention is made to possible swimming pool applications of the concept.]

    Thomas, Jerome qtd. in Paul Konrad. “Whose Numbers Tell the Story?” Pool and Spa News (10 Apr. 1989): 22–26. [Dr. Thomas, successor to Dr. Langelier at UC Berkeley, is quoted in this article. He maintains that the Langelier Index “has no significance to open bodies of water – including swimming pools and spas.”]


    However, John A. Wojtowicz wrote several articles and did experiments showing that a true LSI (not the one the pool industry uses, but one similar to Langeleir's original and similar to my CSI) was applicable. Some of his articles are the following:

    Swimming Pool Water Balance – Part 4: Calcium Carbonate Precipitation Potential

    Although the calcium carbonate saturation index is applicable to swimming pool water balance calculations, it is only a qualitative indicator of calcium carbonate precipitation since it does not indicate the extent of precipitation that can occur at positive values of SI. Utilizing the mathematics of aqueous carbonate and cyanurate equilibria allows calculation of the quantitative calcium carbonate precipitation potential (CCPP), ie, the equivalent calcium carbonate supersaturation. Precipitation of calcium carbonate is accompanied by a drop in pH and a reduction in hardness of 1 mol and in total alkalinity of 2 equivalents for each mol of calcium carbonate precipitated. The calcium carbonate precipitation potential increases with saturation index and buffer intensity. Buffer intensity in turn is a function of pH and total alkalinity. Because buffer intensity decreases with increasing pH, the CCPP also decreases as pH is increased. Cyanurate contributes to total alkalinity, thus it inreases the CCPP for a given carbonate alkalinity. At constant pH, carbonate alkalinity, and calcium hardness, the CCPP decreases with increasing TDS due to a decrease in SI. In part 5 of this series, laboratory data on the precipitation of calcium carbonate under different conditions will be presented and interpreted.

    Swimming Pool Water Balance Part 5: Factors Affecting Precipitation of Calcium Carbonate

    Laboratory tests with clear solutions showed that precipitation of calcium carbonate does not occur in the pH range 7.5 to 8.0 at alkalinities of 80 to 160 ppm and saturation indexes as high as 1.5. However, when the alkalinities are increased to very high levels, i.e., ~460 to ~325 ppm over the same pH range, evidence of precipitation was observed in the 0.5 to 1.1 saturation index (SI) range. At typical swimming pool pH and alkalinity, seed crystals are necessary to initiate precipitation of calcium carbonate supersaturation. Suspended particulate matter can serve as seed crystals. Results of laboratory studies on precipitation of calcium carbonate in the presence of seed crystals are in general agreement with predictions based on the calcium carbonate precipitation potential (CCPP) model discussed in a previous article (Wojtowicz 1996). The results can be summarized as follows: a) at a given initial pH and alkalinity, the extent of precipitation increases with increasing SI, b) at a given initial pH and SI, the extent of precipitation increases with increasing alkalinity, c) at a given initial alkalinity and SI, the extent of precipitation decreases with increasing pH, and d) at a given initial pH, SI, and carbonate alkalinity, the extent of precipitation increases with increasing cyanuric acid concentration due to increased buffer intensity.

    Swimming Pool Water Balance Part 6: Applicability of The Langelier Saturation Index to Swimming Pools

    It is a common misconception that the Langelier Saturation Index applies only to closed systems because it was developed for water in distribution lines. Since it is based on calcium carbonate solubility equilibria, the Langelier Saturation Index is applicable to both open and closed systems containing dissolved calcium carbonate. The main difference is that in closed systems the alkalinity can vary at a given pH whereas in equilibrated open systems alkalinity is fixed at a given pH. In addition, since alkalinities are much lower in equilibrated open systems at comparable pH values, saturation hardness is much higher. Another common misconception is that swimming pools are equilibrated open systems. Although swimming pools are open in a physical sense, they are not open in a thermodynamic (i.e., chemical equilibrium) sense. Swimming pools exhibit the characteristics of closed systems since they show the expected range and variability of alkalinity which is also typical of many public water supplies. If swimming pools were equilibrated open systems (i.e., in equilibrium with atmospheric carbon dioxide), they would contain only 4 to 18 ppm alkalinity over the 7.2 to 7.8 pH range. At a given pH and alkalinity, swimming pools have the same concentration of dissolved CO2 as a closed system. In order to attain equilibrium with the atmosphere, swimming pools would have to lose the excess carbon dioxide that they contain above the equilibrium value of 0.45 ppm. This will cause an increase in pH where higher alkalinities are allowed. However, although swimming pools are open to the atmosphere, they never achieve equilibrium with the atmosphere because of acid addition, which in combination with continual carbon dioxide loss causes the pH to vary with time resembling a sawtoooth pattern.

    Swimming Pool Water Balance Part 7: A Revised and Updated Saturation Index Equation

    At a given temperature, swimming pool water chemistry must be balanced by adjusting pH, carbonate alkalinity, and calcium hardness in order to maintain the proper saturation with respect to calcium carbonate to avoid etching of concrete, plaster, and tile grout, scaling, and cloudy water. Water balance is determined by means of the calcium carbonate saturation index (SI), which was originally proposed to provide corrosion control for iron pipes in public water distribution systems by means of deposition of thin films of CaCO3 (Langelier 1936). The current saturation index equation is based on calcium carbonate solubility data published in 1929. This paper discusses revisions to the saturation index equation due to more accurate values for the calcium carbonate solubility product constant and its temperature dependence and more realistic ionic strength corrections. The revised equation is: SI = pH + Log [Hard] + Log [Alk] + TC + C where both hardness and alkalinity are expressed in ppm CaCO3, TC is the temperature correction, and C = –11.30 – 0.333 Log TDS. The equation requires a reasonably accurate value of total dissolved solids (TDS). At 1000 ppm TDS, C is equal to 12.3. Above 1000 ppm TDS, this equation yields significantly lower values for SI than the current equation.

    Swimming Pool Water Balance Part 8: The Thermodynamic Basis of the Saturation Index

    Thermodynamics (i.e., the laws governing the conversion of heat to and from other forms of energy) is the logical discipline for the mathematical treatment of chemical reactions in homogeneous and heterogeneous systems. The sign of the free energy change as an indicator of the direction of a reaction was known in 1886 (Van’t Hoff) under the name “reaction isotherm”. The free energy change is a measure of the useful energy available from a system. When applied to solutions of calcium carbonate, the expression for the free energy change for a reaction readily and naturally leads to the calcium carbonate saturation index. The equation that bears Langelier’s name, derived from ionic equilibria, is not novel. Therefore, a more appropriate name would be calcium carbonate saturation index as Langelier originally named it (Langelier 1936).

    Swimming Pool Water Balance Part 9: Corrections, Potential Errrors, and Significance of the Saturation Index

    Calculation of the saturation index requires a knowledge of the water temperature and the concentrations of total alkalinity, calcium hardness, and cyanuric acid. Total alkalinity must be corrected for cyanuric acid present as cyanurate ion as well as the concentrations of other significant alkaline species. In addition, the concentrations of complex forming ions other than bicarbonate such as sulfate and magnesium are required. Although these ions decrease the saturation index by reducing the concentrations of calcium hardness and carbonate alkalinity through ion pair formation, the effect is small except at very high levels of these ions. Cumulative errors in typical swimming pool test kit analysis can result in a potential deviation in the calculated saturation index of ±0.14 for water with 120 ppm total alkalinity, 300 ppm calcium hardness, and 100 ppm cyanuric acid. The saturation index is not a corrosion index but rather a scaling index, ie, it is an indicator of the calcium carbonate scaling or scale dissolving tendency of water and not of corrosion.
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by chem geek
    The saturation index is not a corrosion index but rather a scaling index, ie, it is an indicator of the calcium carbonate scaling or scale dissolving tendency of water and not of corrosion.
    This is, IMHO, the most important statement here. For some other opinions on precidticing the corrsive effects of water then this link has an interesting discussion.

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    Applicable or not the LSI is written into many warranty statements for pool equipment. If for no other reason, it should still be considered.
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by waterbear
    Quote Originally Posted by chem geek
    The saturation index is not a corrosion index but rather a scaling index, ie, it is an indicator of the calcium carbonate scaling or scale dissolving tendency of water and not of corrosion.
    This is, IMHO, the most important statement here. For some other opinions on precidticing the corrsive effects of water then this link has an interesting discussion.
    That link is all about metal corrosion, and I completely agree that the LSI or CSI are not useful for predicting metal corrosion. However, it is still true that if you've got calcium carbonate solid in your pool wall, then if the water is not saturated with calcium carbonate then there is the potential for dissolving the calcium carbonate in the wall. The problem is that though there may only be a small amount of calcium carbonate in pool plaster (from impure aggregate or impure Portland cement), its mostly calcium oxide in a hydrated silicate. Thermodynamically, the calcium oxide wants to combine with carbon dioxide in the water to form calcium and carbonate ions. The only question is one of rate and the index doesn't predict that at all.

    Perhaps a new word is needed instead of corrosion when referring to the potential to dissolve, pit, or otherwise breakdown plaster/gunite/grout surfaces. Corrosion seems to invoke the idea of metal corrosion for which the index is not useful. Wojtowicz used the term "scale dissolving" but the calcium carbonate does not have to be that formed from scale, but could be in the pool surfaces when initially constructed. Perhaps "calcium carbonate dissolving" would be the more appropriate term. Another industry term for water with a low saturation index is "aggressive".

    Richard
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    How about using the tern "etching" since that is essentially what we are talking about.

    The link I gave talks about more than just corrosion of metals in water. It gives a pretty good overview of some of the different saturation indicies,

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    I am working with chem geek's spreadsheet to keep my pool in balance. I've been watching the LSI and CSI and it is usually negative. I have some kind of gunite pool, although it is more modern. Not pebletek, but something like it.

    FC 7.5
    CYA ~50
    PH 8
    TA 80
    CA 290
    45 Degrees F

    LSI -.20
    CSI -.24

    I was going to bring the PH back to 7.6, then I noticed the LSI went red. Maybe my CA is a bit low, and I am concerned that if I fix this now, everything will be different when the temperature is 88 in April.

    What is the best way to balance out my pool? What should I be adjusting to? I have to factor that I have an SWG and I keep the TA around 80 to reduce PH rise when the SWG is running. When I change the numbers in the spreadsheet, including temperature to 88, and CA to 400, and PH to 7.6, it seems pretty good. Does that mean if my CA is 400 and PH 7.6 in the winter, I'm losing my plaster each year?
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    Spa: 485 gallon in-ground square acrylic over fiberglass suspended over gunite Sunset brand spa, isolated system, natural gas heater, 2-speed (4hp/11hp) main pump, 3hp booster pump, chlorine sanitized.

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Just leave the pH up closer to 8.0. Because the water is so cold, the pH would naturally be up higher anyway (as water gets colder, the pH rises a bit and this keeps the saturation index more stable). No need to lower it except to make sure you can read it on the pH test (i.e. to know it's 8.0 and not 8.4 or something like that). It's not a big deal, but I'd just leave the pH higher until the temperatures get warmer.

    If you lowered your pH in the winter, you would increase the risk of a very slow dissolving of plaster (slower due to colder temperature). Just let the water "do its thing" by letting the pH rise naturally a bit when the water is colder.

    What TDS did you use? When I plug in your numbers and use 3200 ppm for TDS (for 3041 ppm salt) I get a CSI of -0.18.
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    heh, finally getting back, now that I am opening the pool.

    I used a TDS of 3500.

    Now that it's open, I have
    fc 3
    ph 7.8
    cya 30
    alk 80
    hard 230
    salt at 2100 (says the electronic meter)

    LSA is at 0.16.

    I added 2 cups of acid to go to 7.6 because I know the salt sell will increase it over 2-3 weeks, and I know we're going to run the water effects a lot. That brought LSA down to -.33.

    I'm thinking my hardness is low. Should I kick it up to 400, or even more?

    Ian
    Location: Atlanta, Georgia.
    Pool: 15,000 gallon 32'x18', 3'-6' deep in-ground gunite pool, Sta-Rite 3 125 GPM 2-filter cartrige, 1.5 HP Sta-Rite pump, solar heater, Goldline SWG, Jandy controls, opaque automatic CoverStar solar pool cover, 3 waterfalls (not from spa).
    Spa: 485 gallon in-ground square acrylic over fiberglass suspended over gunite Sunset brand spa, isolated system, natural gas heater, 2-speed (4hp/11hp) main pump, 3hp booster pump, chlorine sanitized.

    To my pool store owner, nothing is more important than my pool and my money.

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    No, not 400. You want your calcium saturation to be a little negative. You do want to bump up your CH level a little. The recommended CH level is between 250 and 350.
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by chem geek View Post
    However, John A. Wojtowicz wrote several articles and did experiments showing that a true LSI (not the one the pool industry uses, but one similar to Langeleir's original and similar to my CSI) was applicable.
    Being in the pool industry for the past 10 years, out in the field servicing pools, all you hear about is LSI. And it is LSI that everyone and companies in the industry uses and refers to.

    Then you come here where there is excellent info for the pool owner, probably the best on the net, on how to properly maintain a pool.

    I'd like to know is, who is the main chemist here at TFP, or is there a group of chemist? Did "chem geek" develop the CSI used by here at TFP?

    If LSI is so prevalent in the industry are there those in the industry that would argue with CSI being more relevant than LSI?

    Is it possible that the industry will eventually switch to CSI?

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    It has been a group effort over the years. We've had lots of input from folks in the industry over the years. Chem Geek is Richard Falk who is a prominent chemist in the pool industry. We also have OnBalance contributing who is a plaster council of industry experts contributing.

    More from onbalance about saturation indices here, Is the Saturation Index always Reliable?

    Our current most active chemistry geek is JoyfulNoise who likes to use big chemistry words. Im sure he'll be along soon to talk shop.
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by pooldv View Post
    It has been a group effort over the years. We've had lots of input from folks in the industry over the years. Chem Geek is Richard Falk who is a prominent chemist in the pool industry. We also have OnBalance contributing who is a plaster council of industry experts contributing.

    More from onbalance about saturation indices here, Is the Saturation Index always Reliable?

    Our current most active chemistry geek is JoyfulNoise who likes to use big chemistry words. Im sure he'll be along soon to talk shop.
    Richard is no chemist (at least he won't admit to being one...). I believe his actual degrees from many years ago is in physics and I think his vocation for many years was in digital imagine processing algorithms (probably works for HP or some other big Silicon Valley tech firm). I'm stating that from memory so I could be totally wrong. If you want his complete CV, I suggest e-mailing him.

    What Richard is is just someone who took a very keen interest in his pool and wanted to know the actual "why's" and "how's" of pool chemistry and refused to simply buy into all the marketing hype and industry guidelines. Rather, using his training in science, he just derived things from first principles and, lo and behold, proved that most of the industry had no clue as to what they are talking about. Richard is a very smart guy and he's probably one of the best resources on the internet to ask questions of because, if it involves pool water in any way, he's probably read at least 10 peer-reviewed scientific papers on the subject matter. The very fact that he, as a citizen-scientist, was ask to join the CDC's Model Aquatic Health Code (MAHC) working group, which is involved in re-writing recreational aquatic code standards, shows just how dedicated he is.

    (Oh, and he's gone over to the Dark Side of the Force and is working closely with a pool industry startup developing some very interesting tech....but shhhhhh, you didn't hear me say that.....)

    As Danny has said, this site is a group effort. onBlanace is the man you talk to about plaster, JamesW...well, I haven't figured him totally out but he's the guy you talk to if you need some deep dark secret revealed about anything related to pool equipment or pool care (he's kind of like Dumbledore...only I'm not so sure he has the cool accent), bdavis466 is the man you talk to if you want to know how to build a pool the right way (he can also frame up some sweet rafters if you need a new roof!), mas985 is the man of hydraulic mystery, if water moves then he knows about it, ps0303 & poolclown will fix your heaters by simply willing them to be fixed using the force (kind of like Obi-Wan Kenobi but without the cool robes)....

    ....as for me, I'm just a schlub with a pool who is destined to meet his end in some fiery explosion of smoked meats that takes out half my neighborhood block....


    Quote Originally Posted by Parabolic View Post
    Being in the pool industry for the past 10 years, out in the field servicing pools, all you hear about is LSI. And it is LSI that everyone and companies in the industry uses and refers to.

    Then you come here where there is excellent info for the pool owner, probably the best on the net, on how to properly maintain a pool.

    I'd like to know is, who is the main chemist here at TFP, or is there a group of chemist? Did "chem geek" develop the CSI used by here at TFP?

    If LSI is so prevalent in the industry are there those in the industry that would argue with CSI being more relevant than LSI?

    Is it possible that the industry will eventually switch to CSI?
    So, to keep it simple, LSI and CSI are practically the same thing. Here's the deal - LSI was developed in the mid 1900's by...Robert Langlier. He was tasked by the water boiler industry to come up with a simple way to understand how water could become corrosive to metal pipes and how to predict if scale would occur. Using lots of empirical data and some science, he developed a scaling index (a mathematical formula that uses measurable parameters as inputs) to predict if water could become corrosive or scaling in terms of calcium carbonate. This was developed for closed-loop water boilers where you want water to be slightly positive in it's scaling index so a thin layer of calcium carbonate in your metal pipes would remain intact.

    The problem was, a lot of the formula was developed based on empirical data and, since this was the 1940's, there wasn't a lot of accurate data for the fundamental chemical constants of various water constituents. As well, the LSI essentially used a "fudge factor" to account for the effects of high TDS and temperature. All of this was certainly fine to use at the time, but it was not based on fundamental derivations from chemical equations, what one would call "first principles".

    Fast forward to the 1970's and a man by the name of John A. Wojtowicz comes onto the pool water scene and does A LOT of fundamental scientific studies of various pool water chemistry issues. He also is responsible for much of the understanding of how cyanurates buffer chlorine which was originally developed in a scientific paper by O'Brien, et al.. Mr. Wojtowicz was dissatisfied with the LSI as a chemistry concept because there had been so many advances in the chemical knowledge since Robert Langlier's day and so he sought to develop, from first principles, the structure of a saturation index that would actually take into account all of the relevant chemistry with respect to the types of compounds one finds in pool water. There are a series of papers HERE if you have the stomach for reading science. In those papers, Wojtowicz outlines the derivation of the CSI and shows exactly how various factors like temperature and TDS come into play. The number one gets from a CSI calculation may be quantitatively different than an LSI number, but they essentially point to the same thing - water is either balanced, scaling or corrosive towards calcium carbonate (ie, one of the major components in plaster surfaces). LSI and CSI tell you nothing about the rates of scaling or corrosion, simply if it exists or not. It also has nothing to do with metal corrosion, ie rust, although people and the industry routinely cite LSI as a measure of metal corrosion (that is simply wrong).

    So, I wouldn't get too hung up on the "which is better" debate as that is a false-choice. The indices are simply measures of how stable calcium carbonate is in solution. You can use one or the other and both will give you the same general answer.

    Also, I believe the Taylor Watergram wheel calculates CSI so, if I'm correct on that point, there you have it - someone else in the industry uses it.
    Matt
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Wow, I read the whole thing! Nice summary.
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Yes. Great overview. Thanks.


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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    I am glad you let OnBalance submit his views here. I think his group is on a good track.

    There was a recent video put out by Orenda about a pool startup and the affect of proper Calcium and Saturation Index
    Imagine reducing plaster dust before startups... - YouTube . I think they are a bit full of themselves calling it a "groundbreaking Orenda startup". Some plasters and startup guys have been doing proper LSI/CSI fills for longer than they've been in business I'm sure. But interesting video none the less.

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by JoyfulNoise View Post
    Also, I believe the Taylor Watergram wheel calculates CSI so, if I'm correct on that point, there you have it - someone else in the industry uses it.
    OK so I ran into a Taylor rep at the pool supply store this week and asked him about the water wheel. He said the Taylor water wheel calculates Langelier Saturation Index (LSI) and pointed me to page 48 in the recent instruction booklet that comes with the complete test kits. So I guess we are back to, no one in the industry using CSI at this point.

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Ok. Good to know.

    Considering how uniformed a lot of the industry is in terms of the actual science behind pool care, Im not too worried about what is taught here. Remember that the industry still teaches people that an FC of 1 to 4ppm is perfectly fine irrespective of stabilizer levels and that a CYA over 100ppm is totally fine. What the industry teaches is what leads most people to having clouded nasty water at least once per season and causes pool owners no end of financial loss with all of the bogus chemicals that are pushed to fix a problem that is caused mainly by what the industry says is sufficient. There are certainly good and smart people in the industry who do care but they are few and far between.

    Also, try not to get too hung up on CSI versus LSI and which one is better. They are just tools one uses to know what the scaling potential of water is. Its like saying my Snap-On wrench is better than your Craftsman wrench at tightening a nut & bolt...really, the wrench doesnt matter. Knowing how tight to make the nut is the more important bit of information. If you prefer to use the LSI/WaterWheel for convenience, then no harm/no foul. Though if you decide to post numbers and ask questions here, TFP would prefer you post a CSI value to make it easier to help give advice.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  18. Back To Top    #18

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by JoyfulNoise View Post
    Ok. Good to know.

    Considering how uniformed a lot of the industry is in terms of the actual science behind pool care, Im not too worried about what is taught here. Remember that the industry still teaches people that an FC of 1 to 4ppm is perfectly fine irrespective of stabilizer levels and that a CYA over 100ppm is totally fine. What the industry teaches is what leads most people to having clouded nasty water at least once per season and causes pool owners no end of financial loss with all of the bogus chemicals that are pushed to fix a problem that is caused mainly by what the industry says is sufficient. There are certainly good and smart people in the industry who do care but they are few and far between.

    Also, try not to get too hung up on CSI versus LSI and which one is better. They are just tools one uses to know what the scaling potential of water is. Its like saying my Snap-On wrench is better than your Craftsman wrench at tightening a nut & bolt...really, the wrench doesnt matter. Knowing how tight to make the nut is the more important bit of information. If you prefer to use the LSI/WaterWheel for convenience, then no harm/no foul. Though if you decide to post numbers and ask questions here, TFP would prefer you post a CSI value to make it easier to help give advice.
    Well not necessarily in "The Industry" I seem to be around. Pool guys have had the material from Robert Lowry which has taught the CYA/FC correlation long before the TFP started teaching this concept. You can find his detailed material from ipssa or his personal website at http://www.lowrycg.com/ . I know that other groups like UPA and CPA also refer members to his materials.

    He has some great apps out as well. And a simplified water chemistry book from Amazon called "Pool Chemistry For Service Pros" https://www.amazon.com/Pool-Chemistr.../dp/B07B43FDT1

  19. Back To Top    #19
    JoyfulNoise's Avatar
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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Read this thread - Nice Little Read..

    Richard Falk (aka, chem geek) and Ben Powell (pooldoc on the The Pool Forum) discovered and quantified the FC/CYA relationship long before the industry ever did, including Lowry. Lowry consulted with both Richard and Ben on his books. Lowrys contribution is that he was the only industry insider that would listen to Richard or Ben and he helped to mainstream some of those ideas. However, Lowry remains very much an inside player in the pool industry and pushes the more dubious aspects of pool care.

    TFP is a direct offshoot of The Pool Forum (members of the PF broke off and started TFP) and its basis is in the work that Ben and Richard did. Ben Powell was running the Pool Forum as an e-mail listserv (PoolSolutions Inc) back in the mid/late 90s and TFP started in 2007 around the same time as Lowry was talking about the FC/CYA relationship (hmmmm....wonder where he heard about that ) . TFP has reached hundreds of thousands of pool owners with the basic principles of DIY pool care. The number of unique users visiting the TFP website and viewing the information presented here is all the reassurance that is needed that TFP is on the right track. The industry still clings to its old ways and, truth be told, they can be made to work by a dedicated pool service pro, but what is taught here is not meant for pros. TFP teaches average ordinary people how to take control and care for their own pools themselves with easy to use methods. Most people prefer to do things on their own if they can to save themselves time and money. Unfortunately pool care can seem like a daunting task and so TFP strives to demystify that perception and make pool care as simple, easy and cost effective as possible.
    Matt
    16k IG PebbleTec pool, 650gal spa, spillway and waterfall, 3HP IntelliFlo VS / 1.5HP WhisperFlo, Pentair QuadDE-100 filter, IC40 SWCG, MasterTemp 400k BTU/hr NG heater, KreepyKrauly suction-side cleaner Dolphin S300i robot, EasyTouch controls, city water, K-1001, K-2006 and K-1766 test kits, Mannitol test for borates

  20. Back To Top    #20

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    Re: Langelier and Calcite Saturation Indices (LSI and CSI)

    Quote Originally Posted by JoyfulNoise View Post
    SNIP...However, Lowry remains very much an inside player in the pool industry and pushes the more dubious aspects of pool care....SNIP
    Yeah I remember reading the Pool Forum before finding TFP, but haven't been there in awhile and now I see it looks like it is locked. But did not know of these relationships.

    Reading more here a found link here to an article that Aqua Magazine did which says "Lowry also cites chemist Ben Powell for first developing the 7.5 percent concept back in the '70s."

    But can you be specific on what exactly those dubious aspects of pool care he pushes are?

    Always learning

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