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Thread: Sequence of chemistry adjustments with fresh pool water?

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    Sequence of chemistry adjustments with fresh pool water?

    Hi,

    I am fixing to drain my pool (full drain, not just partway) as soon as we have another day where it is not 100+ degrees outside. Several chemistry measures are off the scale when I tested them, and the previous owner did not drain the water for the past 7 years. Once I do this and replace the water, in what order should I adjust the various chemistry elements of the water (e.g. total alkalinity first, calcium hardness second, Ph third, and so on)? Such a sequence is not immediately obvious in what I have read in other forums here and on the Pool School (I enjoyed the thoroughness of the PS articles, however!).

    Details about my pool are:

    1. Located in Phoenix, AZ.
    2. Pool is in-ground pebbletech with an attached spa.
    3. Estimated pool size = 8000 gallons + 500 for spa.
    4. Sand filter, chlorinated system, with pop-ups in the bottom.
    5. I do not know the pump size; I'll look again this evening.
    6. Pool was built by Shasta Pools 15 years ago.

    It is interesting to note that if I were to have Shasta come out and walk me through the operation of the pool systems and/or perform any repairs/draining (the heater apparently does not work), they'd charge $180 per hour! To this site's credit, the pool school and forums helped me to avoid the high feels so far!

    Thank you in advance for your help on this topic!

    Cheers,

    Alan
    19,400 Gallon Outdoor In-Ground 18x38 Plaster Pool w/ Intellichlor SWG, Pentair Whisper Flo 1 HP, Pentair Triton C Sand Filter

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    Casey's Avatar
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    Re: Sequence of chemistry adjustments with fresh pool water?

    Hello and welcome to TFP!

    Can you post a full set of numbers so we can see or maybe save you from draining your whole pool?
    I'd bet you my bikini you'll never get TFP water from a pool store!

    24' Sharkline Venture De Filter

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    Join Date
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    Re: Sequence of chemistry adjustments with fresh pool water?

    Also the pH/TA/CH from your fill water, to see if that would actually help.
    In general the main reason to refill is because of super high CYA, second would be high CH. But your fill water also has sky-high CH, a refill won't help.
    --paulr
    BBB "Intermediate Swimmer"
    IG plaster pool 18.5K gal, Hayward Pro-Grid DE filter, 3/4 HP Hydramax II; Polaris 380, 3/4 HP booster
    AG spa 325 gal, probably Sundance of some kind
    Water testing instructions on one page

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    JasonLion's Avatar
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    Re: Sequence of chemistry adjustments with fresh pool water?

    The order you want to do things in depends on what your current levels are. If you are going to do a drain and refill, the important levels are the levels of your fill water. If you test your fill water, we can give you specific recommendations.
    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: Sequence of chemistry adjustments with fresh pool water?

    I decided to go ahead with the drain and refill. I pieced together an arrangement to drain and refill faster than typical. Gotta love a public works department that does stuff on Saturdays, among other things....

    The water was last drained 7 years ago. The CYA was off the scale (as in, well below the 100 line on my tester before the black dot was blotted out). Calcium hardness was pegged at 425 (test used measured in 25 increments). As I understand it, the only way to lower the CYA and CH is to replace water. All three of these together screamed "drain and refill" quite loudly to me.

    As a result of the drain/refill, calcium hardness is now 240. I am attempting to get the alkalinity down from 220 to ~120, since recommendations outside this site say to start with the alkalinity. After alkalinity, I am unclear as to which item to balance in the water next, which is what my question deals with -- In what sequence should the various elements be balanced?

    The pool store tried to tell me that the next step is to shock the pool with 5 ppm chlorine....I felt charged with energy after that discussion!

    Cheers,

    Alan
    19,400 Gallon Outdoor In-Ground 18x38 Plaster Pool w/ Intellichlor SWG, Pentair Whisper Flo 1 HP, Pentair Triton C Sand Filter

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    Re: Sequence of chemistry adjustments with fresh pool water?

    Quote Originally Posted by Hellsing
    I decided to go ahead with the drain and refill. I pieced together an arrangement to drain and refill faster than typical. Gotta love a public works department that does stuff on Saturdays, among other things....

    The water was last drained 7 years ago. The CYA was off the scale (as in, well below the 100 line on my tester before the black dot was blotted out). Calcium hardness was pegged at 425 (test used measured in 25 increments). As I understand it, the only way to lower the CYA and CH is to replace water. All three of these together screamed "drain and refill" quite loudly to me.

    As a result of the drain/refill, calcium hardness is now 240. I am attempting to get the alkalinity down from 220 to ~120, since recommendations outside this site say to start with the alkalinity. After alkalinity, I am unclear as to which item to balance in the water next, which is what my question deals with -- In what sequence should the various elements be balanced?

    The pool store tried to tell me that the next step is to shock the pool with 5 ppm chlorine....I felt charged with energy after that discussion!

    Cheers,

    Alan
    If you could post a full set of current test results it will be much easier to give you direction. Without those its tough to tell you.
    Kidney shaped ~ 10000 gallon Ig Plaster pool with pool cage. 120sf Cartridge filter. Pentair WhisperFlo WFDS-26, 230 Volt, 7.8/3.0 Amp, 1-1/2 Horsepower 2 speed pump, Solar panels on the roof. Heliotrope HelioMatic 4000D solar controller.

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    Re: Sequence of chemistry adjustments with fresh pool water?

    Well, actually, the first thing I would do is pour 1/2 of the small jugs of clorox (FC is currently zero with a refill)into my pool each night.....that'll help keep it clear and sanitary while you are adjusting.

    Next, I would add enough CYA stabilizer to my pool (It's zero afer a refill) to bring it uo to around 40ppm.....it'll take a few days to register on the test so don't backwash.

    Simultaneously with the CYA, I would test the pH and make sure the pool was in the mid 7's.

    You know your CH and it's fine where it is.

    At this point, you could continue the rest of the summer by measuring and testing your FC and adjusting your daily dosage accordingly or you could shock the pool to simply be certain you have no organics left.

    After you're all balanced and you've figured how much chlorine you need daily, you can read how to lower your TA up ion Pool School.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    frustratedpoolmom's Avatar
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    Re: Sequence of chemistry adjustments with fresh pool water?

    I agree with Dave, prevention of algae is the most important thing now, the TA can wait...
    Helpful links: Pool School; CYA/Chlorine Chart
    24' round AG pool, 52" high, Raypak heater; Waterway 2 spd Pump;
    150 Sq ft. Clearwater Cartridge Filter; Former and DISSATISFIED "Pool Frog" owner
    http://www.PerfectlyClearPoolService.com

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