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Thread: Water Temp On closing and Algae

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    Water Temp On closing and Algae

    Not sure I understand the common logic of waiting for the pool water to drop below 65 or 60 degrees before closing. My water is at 72 right now, next week outside temps are suppose to go into the 80's.. Assuming I close with my solid cover today and the temps rise and my chlorine levels don't hold...I suppose the logic is I'll get an algae bloom. OK, but that algae will continue to survive in 30 degree water temperatures all winter long till I open in the spring?

    Opinions please...
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    Re: Water Temp On closing and Algae

    The algae might not survive, but their effect will. If the water is clear when you close and you close when it's too cold for algae to grow; then when you open in late winter early spring, the chances are much greater that you will still be clear.
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    Re: Water Temp On closing and Algae

    We recommend colder water at closing simply because organic matter activity slows down dramatically. This reduces the likely hood of a major algae outbreak. In addition, the colder water couple with less sunlight, uses far less chlorine. Closing/covering your pool at warmer temps only locks-in active organic material increasing the potential for an outbreak.
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    Re: Water Temp On closing and Algae

    A frozen block of green ice in winter is green water in the spring.

    I'm one here who is not hard-lined on closing late or opening early, but as with all TFP recommendations you should be prepared to deal with the aftermath of not following them. I help close pools with warm water and they almost universally need cleared in the spring, but that is the owner's decision and their money to spend clearing it up. I follow the 60 degree rule with my own pool and not only do I open to clear water but I also still have measurable chlorine in my pool when I open nearly 6 months later. Last year I actually didn't have to do a thing to the water upon opening, the levels were perfect. For me it's worth waiting, especially since the lower sun angle and cooler water significantly decreases chlorine usage during those fringe months.
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    Re: Water Temp On closing and Algae

    Thanks for the replies....couple things to note:

    1. I use a hard cover so there will be no sunlight.
    2. My question really revolves around the fact that in a worse case scenario getting an Algae bloom in the fall will have what effect in the spring? Water temperatures will be at least in the 30's.....the algae will be dead...no? Donldson mentions cleaning that up in spring...I get that...but it wont survive correct?

    - - - Updated - - -

    I will say I have never had measurable chlorine upon opening....never been green, but never had chlorine.....I would think opening early is more important closing late.
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    Re: Water Temp On closing and Algae

    Algae doesn't grow in cold water, but that doesn't mean it dies. Even if the algae that was frozen solid were to die (which I don't believe it does) an IG pool never freezes through. There will be plenty of live algae in the pool, just waiting for its chance.
    JD - 28' Round Above Ground Pool, 17,000 Gallons. Dual speed Jacuzzi pump with cartridge filter. Dual speed 1 HP pump, Hayward S210T sand filter
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    Re: Water Temp On closing and Algae

    I close my pool every year mid September, water temps between 68-72. Raise chlorine 2-3 days before closing, insure the pools sparkling clean, close n add poly quat 60

    22 years and it’s crystal clear come spring. But we get cold temps faster than most. Our nighttime temps now hover around 40-60

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    Re: Water Temp On closing and Algae

    Thanks for everyone's input...I'm going to wait a week just to be sure..
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    Re: Water Temp On closing and Algae

    Quote Originally Posted by Pool_Medic View Post
    I close my pool every year mid September, water temps between 68-72. Raise chlorine 2-3 days before closing, insure the pools sparkling clean, close n add poly quat 60

    22 years and it’s crystal clear come spring. But we get cold temps faster than most. Our nighttime temps now hover around 40-60
    Same here. I will be closing Monday and this weekend my pool water is 89 -heater is on. Monday I will put in poly -60. That’s the key.
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    Re: Water Temp On closing and Algae

    Quote Originally Posted by Pool_Medic View Post
    I close my pool every year mid September, water temps between 68-72. Raise chlorine 2-3 days before closing, insure the pools sparkling clean, close n add poly quat 6022 years and it’s crystal clear come spring. But we get cold temps faster than most. Our nighttime temps now hover around 40-60
    Pool Medic:

    One thing missing is the cover. What type of cover do you have? A less expensive mesh cover in Mid September can almost guarantee a problem if the pool is opened late in the spring near the holiday. A solid cover will probably work. My pool was closed Mid September one year by PB (first year only before started doing myself), but he pool was opened super early without a problem. One of the key components is the solid cover.

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    Re: Water Temp On closing and Algae

    Cover or no, I’ve done both ways. Cover just saves leaves from getting in lol

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