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Thread: Cal hypo or 12% liquid shock for pool opening

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    Cal hypo or 12% liquid shock for pool opening

    Every season I use a few lbs of cal hypo (73%) to get the pool cleared up for spring opening (mesh safety cover, so we inevitably have some algae in the pool, and I like to make sure its dead before I start vacuuming to waste)

    I was wondering if Im any better or worse off just dumping in the pool store bleach ("12%", probably really 10% by the time I get it into my pool). The cal hypo has to be ordered online but I can get the pool store stuff locally, and I use it for my Liquidator as well so I need to pick some up anyway.

    I always figured the cal hypo might be a little slower release as the powder has to dissolve. Not sure if its true or not, or if I would blow thru the 12% liquid quicker or not.

    Thanks.

    -Chris
    22K IG vinyl, .5HP Northstar pump, S244T filter, AutoPilot Digital w/SC-48 cell

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    Mod Squad JohnT's Avatar
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    Re: Cal hypo or 12% liquid shock for pool opening

    When you shock, a delay in releasing chlorine isn't what you want. Without knowing your current CH reading or pool type, I couldn't advise any further.
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    JasonLion's Avatar
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    Re: Cal hypo or 12% liquid shock for pool opening

    The only real difference is that cal-hypo adds calcium. You may or may not want to be adding calcium.

    If used properly cal-hypo dissolves almost instantly, so no real difference there.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Cal hypo or 12% liquid shock for pool opening

    Chris,

    I agree...no difference.

    However, I have had a small inconvenince using cal-hypo in the past and wonder if you or anyone else has seen the same thing.

    I don't like to put it directly in the pool....concerned some undissolved may get onto the liner. Therefore, I pour it slowly into the skimmer. In my case. I have a very large intake volume so it dissolves and enters the sytem very nicely.

    If I stay on it (cal-hypo) for a week or so as my regular sanitizer, I will get calcium precipitating onto the clear pump basket strainer lid......making it difficult to see thru. It comes off easily with muriatic but is annoying. Anyone else have this issue?
    Dave S.
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    Re: Cal hypo or 12% liquid shock for pool opening

    Quote Originally Posted by JohnT
    When you shock, a delay in releasing chlorine isn't what you want. Without knowing your current CH reading or pool type, I couldn't advise any further.
    I wasnt thinking a delay from cal hypo would be LONG, its just that inevitably some of it settles out (I dont pre-dissolve it, but I do come back every hour or so to brush it off the floor of the deep end).

    Quote Originally Posted by JasonLion
    The only real difference is that cal-hypo adds calcium. You may or may not want to be adding calcium.

    If used properly cal-hypo dissolves almost instantly, so no real difference there.
    Its a vinyl pool so calcium isnt a problem. Ive used calhypo because of the fact the only thing it adds extra is calcium, and the fact that 1 lb bags are more convenient than 5 gallon carboys. But if I need carboys for regular chlorinating I can just pick up one or two for shocking the pool too. Also nice is the fact that I wouldnt have to worry about brushing it off the bottom of the pool (which brushes algae into the water too). Think I just made up my mind
    22K IG vinyl, .5HP Northstar pump, S244T filter, AutoPilot Digital w/SC-48 cell

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    Re: Cal hypo or 12% liquid shock for pool opening

    Quote Originally Posted by chrisexv6
    Its a vinyl pool so calcium isnt a problem.
    Low calcium isn't a problem with a vinyl pool, but high calcium can cause scaling on any pool surface. If your fill water is high CH or you use Cal-Hypo, it pays to keep an eye on it.
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    cubbybeave08's Avatar
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    Re: Cal hypo or 12% liquid shock for pool opening

    I use the bleach...really Liquid Chlorine...10% but as some of you may already know...Pool mom and I disagree on this...but, I also use a 1 lb bag of Cal Hypo granules about every week on Sunday. I do it as a post weekend Shock because we use the heck out of the pool on the weekend...I am in it all weekend since I miss a lot of weekday swiming...Wife and kids use during the week, but it isn't uncommon to have 7-10 kids in the pool on the weekend at any given time. So on Sunday I throw a bag in through the skimmer. It doesn't raise my Calcium from week to week, infact it keeps it pretty much balanced. Other than that I go with the bleach/liquid Chlorine the other 6 days per week. I have had no problems what so ever.
    Beave
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    Re: Cal hypo or 12% liquid shock for pool opening

    bottom line is this, except for the calcium added to the pool bleach and cal hypo are pretty much interchangeable (as is lithium hypo). Once they are in your water they are all in the form of hypochlroous acid and hyopochlorite ions and chlorinated isocyanurates (if you have CYA in your pool). 1 gal of 10% liquid or 1 lb 73% cal hypo (hard to get these days), 1.75 lbs of 48% cal hypo (what is commonly available) or 2 lbs of 35% lithium hypo will all raise 10 k gallons approx 10 ppm FC. Not exact but close enough for government work!

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    Re: Cal hypo or 12% liquid shock for pool opening

    Quote Originally Posted by waterbear
    1 lb 73% cal hypo (hard to get these days)
    The Leslie's Power Powder Plus in my shed is 73% cal hypo...
    --paulr
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    Re: Cal hypo or 12% liquid shock for pool opening

    Quote Originally Posted by PaulR
    Quote Originally Posted by waterbear
    1 lb 73% cal hypo (hard to get these days)
    The Leslie's Power Powder Plus in my shed is 73% cal hypo...
    --paulr
    Since it is a class III oxidizer the stronger cal hypo formulations are getting harder and harder to find and are being replaced by the weaker class II oxidizer strengths. I am not saying that it can't be found but you might have to do some looking.

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    Re: Cal hypo or 12% liquid shock for pool opening

    intheswim still carries it, thats where i normally get it.

    But, like waterbear mentioned its becoming harder to find, so I except one season Ill wake up and see that intheswim even stopped carrying it. At which point Ill need to use the pool store carboys anyway, so I might as well start now
    22K IG vinyl, .5HP Northstar pump, S244T filter, AutoPilot Digital w/SC-48 cell

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    Re: Cal hypo or 12% liquid shock for pool opening

    http://www.waterwarehouse.com/poolsuppl ... e=19P6022A

    Doheney's water warehouse has Cal Hypo at 73%...I get mine from the local pool store, The Great Escape if you are in Illinois or Indiana. Leslie's also has it but I think more expensive than at TGE or Doheney's...
    Beave
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