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Thread: How quickly does scale or etching occur!

  1. Back To Top    #1

    Join Date
    Jul 2012
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    Central Texas
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    436

    How quickly does scale or etching occur!

    So if I measured my chemistry 2 days ago and we were balanced including LSI and CSI...and then today I measured again and pH was a wee high at 8 with 1 drop needed to bring it down to 7.6, so 9 ounces of MA was added. Tested again a few hours later and everything is nailed on the chemistry.

    So how long does something have to be 'off' before the pool starts being subject to scaling or corrosion? 1 hour and the process starts? 1 day? 1 week?

    Not a panic question...a curiosity question.
    Central TX / 12K GAL / IG / SWG / DE filter / Pentair SVRS & 3 swim jet pumps / Spa bench and jets / Single body of water / No heater.

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    Re: How quickly does scale or etching occur!

    Does anyone have a thought on this? ChemGeek?
    Central TX / 12K GAL / IG / SWG / DE filter / Pentair SVRS & 3 swim jet pumps / Spa bench and jets / Single body of water / No heater.

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    San Rafael, CA USA
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    Re: How quickly does scale or etching occur!

    It's not so much the time as the degree away from balanced CSI and also another factor which is the capacity for change known as the Calcium Carbonate Precipitate Potential (CCPP). Generally, we don't see scaling in pools until the CSI gets to at least +0.7 and especially +1.0 or higher. In hot spas, scaling can sometimes be seen when the CSI is +0.3 or higher. If the CSI gets high to +1.0 or more then scaling could occur in hours but to get a substantial amount of scaling usually requires sustained high CSI over many days. It really depends on how high the CSI gets how quickly.

    As for degradation of plaster, this is usually much slower unless the pH is low. Degradation usually takes months if not years, but again that depends a lot on the pH. It also depends on the quality of the plaster and if it is finished curing. Plaster is most susceptible to dissolving shortly after it has been freshly made and in the weeks after, but after a month or so it should be more resistant, but again depends on how well the plaster was made. Plaster higher in calcium chloride content will be weaker and more susceptible. If you pour strong acid directly onto plaster, it can degrade in seconds to minutes.
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

  4. Back To Top    #4

    Join Date
    Jul 2012
    Location
    Central Texas
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    Re: How quickly does scale or etching occur!

    Thank you. You've given me a better understanding of the timeframes and parameter ranges. I appreciate it.
    Central TX / 12K GAL / IG / SWG / DE filter / Pentair SVRS & 3 swim jet pumps / Spa bench and jets / Single body of water / No heater.

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