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Thread: Alkalinity test question

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    meatloaf's Avatar
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    Alkalinity test question

    When using The Pool Calculator should I be entering the CYA adjusted result or the result straight from the drops test? I usually get my water tested by Shasta Pool and the multiply the CYA by .3 and subtract that from the drops result. I hope I stated this clearly enough.
    Thanks
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

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    Re: Alkalinity test question

    At normal CYA levels (up to about 50 ppm) the adjustment is usually less than the accuracy of the test itself so I would not worry about it. The only time it is an issue is with very high CYA levels....100 ppm or higher.

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    JasonLion's Avatar
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    Re: Alkalinity test question

    My Pool Calculator and the recommended levels at TFP are designed to correspond to the numbers straight from the test kit. The only time you normally need the CYA correction factor is when calculating LSI. The Pool Calculator makes the correction for you when calculating CSI.
    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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    meatloaf's Avatar
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    Re: Alkalinity test question

    My CYA = 70 and Alkalinity = 80. It seemed a bit low to me. PH tends to rise. Should I increase the Alkalinity level?
    Thanks
    My Pool Calculator and the recommended levels at TFP are designed to correspond the numbers straight from the test kit. The only time you normally need the CYA correction factor is when calculating LSI. The Pool Calculator makes the correction for you when calculating CSI.
    Thanks, I shoul have waited a bit for the answer
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

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    Re: Alkalinity test question

    Quote Originally Posted by meatloaf
    My CYA = 70 and Alkalinity = 80. It seemed a bit low to me. PH tends to rise. Should I increase the Alkalinity level?
    Thanks
    If your pH is rising I would lower the TA a bit more, say 60-70 ppm. If you have a plaster pool you will want ot raise your CH accordingly to keep the water balanced.

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    meatloaf's Avatar
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    Re: Alkalinity test question

    CH is 420 right now. Arizona water is very hard.
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

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    lulupalooza's Avatar
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    Re: Alkalinity test question

    Quote Originally Posted by waterbear
    Quote Originally Posted by meatloaf
    My CYA = 70 and Alkalinity = 80. It seemed a bit low to me. PH tends to rise. Should I increase the Alkalinity level?
    Thanks
    If your pH is rising I would lower the TA a bit more, say 60-70 ppm. If you have a plaster pool you will want ot raise your CH accordingly to keep the water balanced.

    waterbear- so if you have a pool who's pH likes to rise to 7.8 and pretty much hold there on it's own. We should keep our TA levels around 70/80?
    *~ Laura ~*
    27x52 Aquasphere Conquest AGP (approx.17,100 gal)
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    BBB User- Salt Added

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    JasonLion's Avatar
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    Re: Alkalinity test question

    If your PH is stable at 7.8 then you can leave your TA where it is.
    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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    Re: Alkalinity test question

    What JasonLion said!

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    AnnaK's Avatar
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    Re: Alkalinity test question

    Quote Originally Posted by JasonLion
    My Pool Calculator and the recommended levels at TFP are designed to correspond to the numbers straight from the test kit. The only time you normally need the CYA correction factor is when calculating LSI. The Pool Calculator makes the correction for you when calculating CSI.

    What do LSI and CSI stand for? I looked in Pool School/Abbreviations but couldn't find those.
    — AnnaK —

    12,000 gal AGP, Hayward sand filter, Pentair 2-speed pump, timer.
    Please visit our Pool Issues pages for information about step weights, managing the solar cover, and PoolSkim.

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    meatloaf's Avatar
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    Re: Alkalinity test question

    The calcite saturation index is a tool for estimating the likelihood of plaster corrosion or calcite scaling. The LSI, Langelier Saturation Index, is a very similar but slightly less acurate measure. The CSI uses PH, TA, CH, CYA, temperature, Borate, and Salt levels to estimate the likelihood of problems. A low saturation index means the water is likely to dissolve calcite out of paster, pebble, tile, stone, and concrete surfaces (and perhaps fiberglass) which will eventually cause damage. A high saturation index means the water is likely to deposit calcite scale on the walls of the pool and in the plumbing.

    CSI is most sensitive to changes in PH. With a plaster pool, it is best to try and get your CSI a little below zero, so that changes in PH won't shift your pool too far towards corrosion or scaling. With a vinyl pool the CSI can be kept more negative, which makes it very unlikely that PH changes could get the CSI into the range of scaling risk.

    This can be found at The Pool Calculator
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

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    Re: Alkalinity test question

    Quote Originally Posted by meatloaf
    This can be found at The Pool Calculator
    Thanks pal. Now I feel like a puppy with her nose rubbed in it.

    Since CSI (NOT the TV show!) apparently requires an esoteric calculation with a slide rule (I do have several of those) and since I have not a clue as to what the formula is, I don't have a hope of figuring that one out. Then again, since I have a liner pool, no heater, no SWG, and PVC plumbing I probably don't need to stress out over it too much. Or do I?
    — AnnaK —

    12,000 gal AGP, Hayward sand filter, Pentair 2-speed pump, timer.
    Please visit our Pool Issues pages for information about step weights, managing the solar cover, and PoolSkim.

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    Re: Alkalinity test question

    You don't want to try and calculate CSI by hand. But my Pool Calculator will do all the math for you, making it very simple to find out in practice. If you really want to calculate something by hand, use LSI.

    LSI and CSI are only important when you have a plaster/pebble pool and are forced to be outside the normally recommended ranges for one or more of your chemical levels. If you stick with the recommended levels you will be fine.
    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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    AnnaK's Avatar
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    Re: Alkalinity test question

    Well, OK then!

    I'm fine, and you're a marvel.
    — AnnaK —

    12,000 gal AGP, Hayward sand filter, Pentair 2-speed pump, timer.
    Please visit our Pool Issues pages for information about step weights, managing the solar cover, and PoolSkim.

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    meatloaf's Avatar
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    Re: Alkalinity test question

    Thanks pal. Now I feel like a puppy with her nose rubbed in it.
    Sorry didn't mean to offend, just trying to help.
    My pool is a 10,500 gallon (420 Sq Ft ) kidney shape. A hand made sheer decent waterfeature. STA-RITE HRPB30, Sand filter 30" 98 GPM,
    1 HP Maxi-Glas 2 pump, BBB Method, Taylor K-2005 test kit, 50 Watt 12V low-voltage pond light illuminates the pool at night for a nice soft glow.
    250 gallon stand-alone hot tub. Got it FREE!

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    AnnaK's Avatar
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    Re: Alkalinity test question

    You didn't offend me, meatloaf. I should have put a
    — AnnaK —

    12,000 gal AGP, Hayward sand filter, Pentair 2-speed pump, timer.
    Please visit our Pool Issues pages for information about step weights, managing the solar cover, and PoolSkim.

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