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Thread: Can't get pool under control

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    Can't get pool under control

    Total alkalinity 260
    Cyanuric acid 200-300
    Calcium Hardness 500
    Free chlorine 0.5-1.0
    Combined chlorine 1.0-2.0
    pH 7.2
    Water temp 82 F
    Air temp range 100 daytime, 50 nighttime, intense sun.
    Water appearance crystal clear, sparkling
    Believe it or not, those are the real numbers.

    Water generally looks good.
    Water always smells good.
    Pool equipment runs 4 hrs each morning. (8am-noon)

    Last year and this year we cannot keep the pH up.
    Last year and this year we cannot keep the FC up.

    The first 3-4 years we had to add acid weekly to correct the pH.
    We have added 10-12 lbs of soda ash and 1 lb of baking soda over last season and this.
    Except for baking soda and soda ash which come generic from Walmart,
    pool is treated with Bioguard brand products.

    We've had green algae, but was taken care of with algaecide, algae killer, and shocking.

    Prob 1: pH won't stay up
    Prob 2: FC won't stay up.
    Prob 3: We know have a stubborn 'red algae' growing on the plaster surfaces.

    Any suggestions?
    14,000 gallons
    cartridge filter (new carts 11/2011)
    In Ground - plaster
    1-2hp pump and 100 g/m filter
    Built/Installed summer '06

  2. Back To Top    #2
    Mod Squad woodyp's Avatar
    Join Date
    Apr 2010
    East Texas

    Re: Can't get pool under control

    Welcome. Before we go any further, where did you get those test results?
    16x32x52" Steel Cornelius Miramar AGP Vinyl liner 13,100 gal. Buried 2 ft.
    2 Speed Hayward Power-Flo Matrix 85 g.p.m. 22" 250lb. sand filter hard plumbed
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    Re: Can't get pool under control

    Taylor K-2005 Complete (high) kit

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    Join Date
    Jun 2010
    Glendale, CA

    Re: Can't get pool under control

    Take some time to go through the pool school articles. Pay special attention to the relationship between FC and CYA.

    Basically your ONLY problem is that your CYA is very very high. This has built up over time from using trichlor pucks to chlorinate the pool. When CYA is high most of the chlorine in the pool is not in active form - it is bound to the CYA and thus does not kill algae.

    So now you are in this vicious cycle - you "shock" the pool with a bit of product. This kills some of the algae - but not all of it. The algae continues to grow - even if you can't see it - and causes your pool to have high chlorine demand.

    The way we deal with shocking here is to elevate the chlorine to shock level (this number is based on CYA). Hold the pool at shock level until ALL the algae is dead and filtered out - and then maintain the pool at the correct chlorine level (again based on CYA). If you manage your pool in this way you will eliminate forever the problems you are having.

    But with a CYA value of 200-300 you'll find it next to impossible to properly shock/maintain the pool. You'd need to get the chlorine up to 80-100ppm to be truly effective - and that's not very practical.

    So you will hear a number of people suggest you drain a good portion of your pool. I'm sure this will sound a bit extreme - but there is no way to remove CYA from the water other than draining it out.
    16K Gal Plaster | Compupool SWG | Intelliflow VF | TF-100

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    elwood58's Avatar
    Join Date
    May 2012
    Sun City West Arizona (2nd Home)

    Re: Can't get pool under control

    You either need to replace your water, or hire an RO Service, which is only available in very limited geographies. Until that CYA number is 50, you are going to continue to struggle with water chemistry.
    14100 Gal IG MiniPebble, Pentair Intellichlor IC-40 SWG, Sand Filter, Pop Up Cleaning, Intelliflo VS Pump, Aquacal Heatpump/Chiller, 1/4 Acre Desert Landscaped, Lots of Deck. Built in 1984, updated in 2012 and 2014
    "If you don't measure it, you can't manage it!"

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    Richard320's Avatar
    Join Date
    Jan 2010
    San Dimas, CA (LA County)

    Re: Can't get pool under control

    My suggestion: stop using trichlor pucks!

    They have built the CYA level up so high that whatever chlorine you actually add is insufficient to overcome algae; you have a stalemate right now, where you kill it as fast as it grows. Hence, unable to hold FC. Trichlor also is acidic, and drives pH down. Hence, unable to keep pH up.

    As long as there's no algae bloom going in, fixing things will be simple but not easy; drain about 3/4 of the water and refill it. You're going to hate doing it. All that time and all those pricey chemicals down the drain (or onto the lawn)

    Once refilled, use bleach as your chlorine source. Expect to need a good amount of acid to keep pH down, as your high TA will tend to push it up. For a change.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Join Date
    Apr 2010
    Buckeye, AZ 85326

    Re: Can't get pool under control

    Listen to the good folks here, read pool school a couple times and your pool will be trouble free real soon.
    11,872 Gallon IG Shotcrete play pool
    Blue Granite Pebble Sheen finish
    Hayward SwimClear c4025, Navigator & Tristar 1.75hp pump
    2' Powerfall

  8. Back To Top    #8

    Re: Can't get pool under control

    Thanks for all the input. I've taken it to heart and have pored over all the articles here. Feel I'm prepared to tackle the problem. Just one thing... the wife says no draining the pool until the season is over. We've had a late and crappy swim season here and she won't give up any more of it. If I don't get this fixed this fall, I'll be back.

    Thank again.

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    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Tucson, AZ

    Re: Can't get pool under control

    BTW, to truly take control, you need to add the FAS-DPD chlorine test to your K-2005 kit (which will make it the recommended K-2006). You can order it at

    It is really not feasible to remove your algae (and FC consumption) problem with the CYA as high as it is ... will certainly cost you more $$$ on chlorine and more time than just replacing the water to get the CYA reasonable.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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    techguy's Avatar
    Join Date
    Jul 2010
    Antelope, CA

    Re: Can't get pool under control

    Is your CYA test based on a reliable source... like the Taylor drop/reagent test? Or is based on test strips or a computer?

    It looks like you need the FAS_DPD add-on kit.
    -- Guy --
    10K gallons in 21' Round 52 inch wall Aqualeader AG, Hayward Power Flow LX 1.5 HP pump motor, Hayward Perflex EC50AC DE filter w/Cellulose, Wide mouth skimmer, 2013 new Diver Dan (craigslist) to replace the faded old Hayward AquaBug. TF-100

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