ep91 Water Balance, LSI

Frank and Jacque talk about water balance water chemistry. Why is LSI Langlier Saturation Index important in your pool and how do you manage it.

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00:00-04:50 must be halloween found a bat in a skimmer, plaster finisher didn't use stainless steel set screws when reinstalling the pool light fixture

04:51 facebook question asking if they should be concerned about pH being high in their pool. answer is a little high or a little low is ok as long as LSI is in a good range. Then people asked what is LSI.

05:40 anyone managing a swimming pool should understand LSI, Langlier Saturation index. LSI is water balance. Water seeks a saturation equilibrium. There. are a few things that determine what that equilibrium is. water temperature, pH, alkalinity, calcium hardness, total dissolved solids, and to a degree cya, borates, and a few other factors. All of these go into a formula that allows you to calculate if the water is aggressive, meaning it wants to dissolve anything it can to become saturated which can etch pool surfaces or weaken and damage equipment, or scaling, which is the water has too much stuff dissolved in it and it wants to push the dissolved materials out of solution, or precipitate, which can cause scaling or staining.

06:45 water chemistry, both balance and sanitizers are just part of pool maintenance. chemistry alone will not keep your pool water looking good and safe. you still need good filtration, circulation, removal of debris, and brushing.

17:45 to achieve proper chemistry you must properly test your water, and do not dose a chemical without testing it first. and measure doses, do not guess amounts. it is recommended that most chemicals, acid, shocks, etc.. be diluted in a bucket of water when adding it to the pool. Always add chemical to water not water to chemicals. keep records for test results, chemicals added, filter pressure, and water condition. There are apps available that can make calculating LSI easy. We like the Orenda app.

Water temperature changes the water balance. as temperatures increase the LSI increases, and as they decrease the LSI decreases. so the average pool LSI will change quite a bit during the year just do to water temperature. typically scale will first develop in areas where the water temperature is a little warmer.

Calcium, on most pools, will naturally increase over time. the only way to decrease calcium in water is to remove or dilute the water, use reverse osmosis, or push it out of solution by violating the lsi and turn it into scale in the pool.

total dissolved solids is everything that has been dissolved into the water

cya and borates affect LSI through their affect on alkalinity test results

Alkalinity is the total of carbonates, bicarbonates, hydroxides and a few other things to a lesser degree. It is called the buffering capacity of water. It resists the effect of acids and bases on the LSI. Too low or too high alkalinity make it difficult to control pH. Alkalinity should be tested weekly and managed pretty closely.

ph has the biggest impact on LSI, and it typically is the parameter in LSI that changes the most. pH can change hourly in a pool. It is extremely important that you test pH regularly and adjust as needed.