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Thread: Cost of liquid shock (chlorine)

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    Cost of liquid shock (chlorine)

    I noticed that kmart and a couple of other stores selling liquid shock which by the label is nothing more than 10 % liquid chlorine, would like to know if 3.99 a gallon is a fair price?


    thanks joe inMandeville,Louisiana
    New owner of a Intex 15 ft. round 5300 gal with 1000 gallon filter pump in Mandeville, Louisiana

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    Ohm_Boy's Avatar
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    Re: Cost of liquid shock

    I suppose that it's about normal. Our Wal-Marts around here have gallons of 10% for $3.97, so we're within a couple of cents of each other.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    reebok's Avatar
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    Re: Cost of liquid shock

    it can vary widely by location, but the main thing is, is it cheaper than bleach (when factoring in strength differences)? also, I'm not sure what kind of turnover those jugs get, so they may have lost a lot of their strength whereas bleach has a higher turnover.
    16x32 21,000 gallon in-ground exposed aggregate, 1.5hp pump, 120 sqft catridge filter, birdcage, solar panels, aquavac tigershark qc robot.

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    Re: Cost of liquid shock

    Quote Originally Posted by reebok
    ...not sure what kind of turnover those jugs get, so they may have lost a lot of their strength whereas bleach has a higher turnover.
    Reebok is right: The higher the percentage of sodium hydroxide (my spelling may be off!) the faster it degrades.
    The price that you've given for 10% isn't bad, but it may only be 8% by the time that you use it. That has to be factored in as well.

    Terry in NC
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    Re: Cost of liquid shock

    I bought 6% today at WalMart: 182 oz. for $2.12...about $1.50 per gallon..
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    frustratedpoolmom's Avatar
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    Re: Cost of liquid shock

    My pool store has 12.5% for $3.00 a gallon, so that price seems kinda steep for 10% to me.
    Helpful links: Pool School; CYA/Chlorine Chart
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    Re: Cost of liquid shock

    It definitely depends on where you are. I get 12.5% from the pool store on sale for $4.99.
    Nicole

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    Re: Cost of liquid shock

    Quote Originally Posted by fuzzy_dba
    [
    Reebok is right: The higher the percentage of sodium hydroxide (my spelling may be off!) the faster it degrades.
    I believe you mean sodium hypochlorite.

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    Re: Cost of liquid shock

    Quote Originally Posted by Jerry
    I bought 6% today at WalMart: 182 oz. for $2.12...about $1.50 per gallon..
    Today I tried Sam's Club...thinking that they would be cheaper than WalMart.
    Only Clorox brand available at $2.70 per 182 oz. (case of 3 bottles)
    ....so store brand is cheaper at WalMart
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    Re: Cost of liquid shock

    Quote Originally Posted by reebok
    ...not sure what kind of turnover those jugs get, so they may have lost a lot of their strength whereas bleach has a higher turnover.
    It's true that bleach will degrade over time but assuming the store keeps it inside at around 75F, the stuff is good for a few months. (Half-life of 10% at 75F is one year.)
    --paulr
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    polyvue's Avatar
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    Re: Cost of liquid shock

    Sodium Hypochlorite 10% Liquid Chlorine

    purchased at Leslie's Pool Supplies in Sacramento, California: $6.59 for 2 gallons.

    for a total (inc. 8.75% sales tax) of $7.17 -- that's $3.58 per gallon.
    14,555 gal in-ground 16'x29' white plaster Pool w/spa (2007); Goldline Aqua Logic AQL-PS-8 control w/Aqua Cell 15 Salt Water Chlorination (SWCG); Hayward TriStar 1HP (1.85 SF) main / 1.5HP (1.60 SF) spa pumps; Hayward Swimclear cart filter C4025, ColorLogic LED lights; Tankless SP-18-4 electric heater; Polaris 280 cleaner.
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    Re: Cost of liquid shock

    ~$4.25 for 10.5% - 2.5 gallons ($1.70 a gallon) here in Tampa/St Pete area. Prices definitely seem to vary depending on where you live.
    ~13000 inground plaster
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    Re: Cost of liquid shock

    Our Wal-Mart has it for sale at $10.95 for a box of two one gal containers. That for 10%.

    The local pool store has 12.5% 5 gal containers for $14.99. They keep it on the sunny side of the store.

    This Wednesday I used 12 gals to get to a FC reading of 19. I wish there was a simple test to find out what the real % is of the chlorine.
    Hotrod30

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    Re: Cost of liquid shock

    Quote Originally Posted by Hotrod30
    I wish there was a simple test to find out what the real % is of the chlorine.
    Maybe not completely simple, but not too bad either:

    1) Measure the FC of your tap water (city water often has some).
    2) Put 4 gallons tap water in a bucket (measure carefully). Add 1/2 tsp bleach. Swirl to mix give it a little while to mix thoroughly. Measure the FC.
    3) Subtract the second FC from the first FC; that's the FC change we can attribute to the bleach.
    4) Take that ppm number, multiply by 0.6, and you get the % hypochlorite for the bleach.

    Because the sensitivity of the FAS-DPD test is +/- 1 drop, for these tests you should use a 25ml sample instead of the usual 10ml; that way each drop is worth 0.2ppm instead of 0.5ppm.

    For example, let's say my tap water shows FC 0.6 and the bucket shows 16.0; the bleach increased FC by 15.4ppm; that would be (15.4 x 0.6 =) 9.2% bleach, call it 9%.
    --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
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    h2ctpdjl's Avatar
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    Re: Cost of liquid shock

    Our local Meijers grocery store sells their 10% liquid "shock" for $9.99 for a case of four full gallon jugs. To me, that price was awsome and the first case I bought was great. After that, it all went down hill. It was obviously old and had degraded so much I had to double the amount I normally used just to maintain my daily FC level. I quit buying it and went back to good ole 6% Bleach from Wally World. My local pool stores want way too much for their liquid chlorine.
    18,000 gal, 18x32 IGP, vinyl liner, 3 to 5.5ft depth. One inlet/skimmer (Aqua Genie), one main drain. Hayward Pro Series Sand Filter w/filtration rate of 20 GPM/FT, Two-Speed Pentair Whisperflo 1 HP pump, Natural Gas Hayward H200 pool heater, Aquabot T2 (200 Series) Robotic Pool Cleaner (my best friend), Automatic Electric Pool Cover (2nd best friend).

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    Re: Cost of liquid shock

    Quote Originally Posted by PaulR



    Because the sensitivity of the FAS-DPD test is +/- 1 drop, for these tests you should use a 25ml sample instead of the usual 10ml; that way each drop is worth 0.2ppm instead of 0.5ppm.

    For example, let's say my tap water shows FC 0.6 and the bucket shows 16.0; the bleach increased FC by 15.4ppm; that would be (15.4 x 0.6 =) 9.2% bleach, call it 9%.
    --paulr

    If you use 25 ml of test water instead of 10 ml, would you use more of the R-0870 DPD power?
    Hotrod30

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    Re: Cost of liquid shock

    No, if you were already using 2 scoops. If you were using only 1 scoop when doing a 10 ml sample, then use 2 scoops with the 25 ml sample.
    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
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    Re: Cost of liquid shock (chlorine)

    Ocean State Job Lot $3.00 per gallon 12%
    15000gal IG plaster pool, cartridge filter

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    Re: Cost of liquid shock (chlorine)

    OK. Here is what I did and the results.

    My wife read the directions and first I checked the chlorine in the pool so she could watch and get use to counting the drops. I use one scoop in 10 ml for normal pool testing.

    I cleaned out the bucket real good (only used in the pool area).
    I opened up 4 new one gal jugs of distilled water (I have a lot of distilled water for my plants).

    She used a ½ tsp measuring spoon (we both checked the measuring spoon size) and measured ½ tsp of 12.5% chlorine from a new 5 gal carboy that I just opened.

    I stirred for about 5 minutes while we talked about the upcoming year; Christmas, kids, grandkids, etc.

    I measured 25 ml in the “chlorine only” container (I’m using a TFP test kit).

    I put in 2 heaping scoops of R-0870 DPD power.

    It took 62 drops until my wife and I were satisfied the test sample was clear.

    So----

    62 drops times .2 is 12.4.
    12.4 times 0.6 is 7.44

    My 5 gal container of 12.5% chlorine is only 7.5% chlorine?

    Is that it or did I do something wrong?

    Maybe that is why when I super shocked the pool last week with 12 gals of chlorine ; two hours later I only got a FC of 19 (started with 0.5).

    After a dirty rain, in 6 days I used 27 gals of chlorine and 20 1# bags of HTH shock to get the chlorine reading back to a steady ten (highest reading was FC of 24) and the pool clear. I believe the bags of shock is what brought the chlorine level up and killed what was in the pool.

    Also, the pool PH went from 7.6 to 6.8. It took 4 boxes of borates to get it back up.
    Hotrod30

    20 X 40 foot vinyl Borates and Salt Pool
    Rolachem Chlorine Feeder
    Hayward 27 inch sand filter with 80 lbs of pea gravel
    Jacuzzi Splash Pak SP55 DE filter in parallel
    Pentair VF3050 pump

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    Re: Cost of liquid shock (chlorine)

    I'm pretty sure I derived the test correctly; this is how I did it.

    chem geek said (according to notes I keep for myself):
    1/8 tsp 6% bleach in 1 gallon is 10ppm.
    (Also: 1 gallon X% bleach in 10,000 gallons is worth X ppm. But I digress.)

    I don't know about you, but I can't measure 1/8 tsp of anything liquid, so I boosted the amounts to something more manageable:
    1/2 tsp 6% bleach in 4 gallons is 10ppm. (multiply tsp and gallons by 4; leaves ppm unchanged.)

    So, that means if 1/2 tsp of X% bleach in 4 gallons is Y ppm, X = 0.6 Y. (derive by algebra)

    How did chem geek get 1/8 tsp per gallon?
    There are (4 x 128 x 6 =) 3072 tsp in 4 gallons, or 6144 half-teaspoons.
    Therefore 1/2 tsp per 4 gallons dilutes by 1:6000 (close enough).
    If your 1/2 tsp is 6% hypochlorite, you have 0.06:6000 hypochlorite, or 0.01:1000, or 10:1,000,000 which is 10ppm. So in this dilution, 6% => 10ppm. (9.8 for the math geeks.)

    If you had 12.5% hypochlorite you should see 20ppm. Assuming the bucket and stirring stick were clean. With two of you watching you probably did count drops correctly. (I guess I was being a little too anal in saying you should use a 25ml sample.)

    --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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