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Thread: Who's right!!

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    Who's right!!

    Ok, just installed a new aqua right generator t-9 for a 25k pool. Added the salt ( 8-40lbs bags. 320 lbs) on Sunday. Generator has been running for about 4 hrs. Question is my new salt test kit Taylor 1766 kit says I have 4100 ppm of salt. The generator says I have 3100 ppm. Who's right? I have to go by what the generator says because it has built in shut down features for over or under salt. But I don't want more salt than what's needed. According to my guess I have a 22k pool. Should not have been 4k ppm with the amount I added? Pool is 16 by 38. 3 /12 ft to 6 1/2 feet. Any comments?
    22K IG. 250 lbs sand filter. SWCG. Fiberglass.

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    Isaac-1's Avatar
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    Re: Who's right!!

    Are you assuming there was no salt in the water when you started? You know bleach/liquid Chlorine breaks down to salt, and I think one of the biproducts of Dichlor, and maybe trichlor is also salt.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
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    Re: Who's right!!

    I did not realize that! You are right. Could explain why the salt level is we're it is with not the amount of salt to call for. But which reading is right? The generator or the test kit?
    22K IG. 250 lbs sand filter. SWCG. Fiberglass.

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    Isaac-1's Avatar
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    Re: Who's right!!

    I think what you have are two different ways to measure, the test kit looks for a chemical concentration of "salt" I am not sure exactly how it does this, and may be "fooled" by "salts" other than what we call table salt or sodium chloride, for example potasium chloride comes to mind. Where the SWG is likely looking at the electrical conductivity of the water, which increases with the addition of salts and potentially other soluble compounds. Either way as you already said you have to make the SWG happy.
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

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    JasonLion's Avatar
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    Re: Who's right!!

    None of the salt tests are better than +-400, so some difference is expected right off. Various things, like cold water, calcium scaling, worn out cell plates, etc, can throw the SWG salt measurement completely.

    Given the amount of salt you added and your likely starting salt level, it makes more sense that reality is closer to the Taylor 1766 test result than the SWG is. But knowing that doesn't help anything. The SWG works based on what it measures the salt level at, it doesn't even matter if it is wrong, that is it's reality and you need to keep it happy, while getting a "correct" result really doesn't help.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Who's right!!

    Makes sense. The more I learn the dumber I get. I will keep swcg happy continue to save hundreds reading here! Thanks! I actually do under most of that.
    22K IG. 250 lbs sand filter. SWCG. Fiberglass.

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    Re: Who's right!!

    Ok this am swcg shows 3400 ppm after have been running for about 14 hrs now. So the tests are about 500 ppm different. Can anyone tell me in a lamens tern how the swcg determines salt content? Now I'm afraid it may go to high. I should have tested the salt before I added it. Thought it would have been zero ( with all my chemistry knowledge )
    22K IG. 250 lbs sand filter. SWCG. Fiberglass.

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    JasonLion's Avatar
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    Re: Who's right!!

    Water never starts with a salt level of zero (expect distilled water). Then, just about every pool chemical includes some salt. The longer you have had your pool in operation, the higher the salt level will be. Typically the salt level when you never intentionally added salt maxes out around 2000 after a couple of years (because there is always some water replacement diluting the added salt). While the salt level will be much lower if you just filled the pool.

    The SWG guesses at the salt level by measuring the electrical resistance of the water. Salt makes water more conductive, more salt makes the water more conductive. Other things, besides salt, can also affect how conductive the water is, but salt is usually the main thing affecting it in practice. Water temperature also affects the conductivity. Some SWG compensate for that, others don't. Another important factor is that the SWG averages the salt reading over 24 hours. Any change in the salt level, say from adding salt, won't be fully reflected in the SWG reading for 24 hours.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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