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Thread: Green Algae

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    Green Algae

    We've been waging an on-going war with green algae this summer. In late July, my husband used silver algaecide (recommended by a local pool cleaning/supply company) and it cleared the pool up - it was sparkling. Then we had some rain and left town on vacation and returned to a green swamp. We tried using the silver algaecide again, but it didn't seem to work at all.

    I have now read everything in Pool School and I've read several posts on how to tackle the algae. I ordered the TF100 test kit today, and I'm hoping it'll be in by this weekend (pleasepleaseplease). My question: given the current state of the pool (dark green and cloudy - 3 ft visibility in shallow end) and the fact that I won't be able to monitor it hourly until I'm off on Saturday, should I do anything to it in the meantime? Should I add a couple of gallons of bleach daily? Run the pump at all? Or just leave it in its current state until I'm able to devote my time to it?

    Jill
    El Paso, Texas
    16x32 Rectangular In-Ground Pool - Plaster - Cartridge Filter - 25,000 gallons - TF100 Test Kit

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    Re: Green Algae

    Wait until you can devote more time. It will just keep comeing back until you kill it all.
    24' 52" Above Ground
    BBB
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    Re: Green Algae

    should I do anything to it in the meantime? Should I add a couple of gallons of bleach daily? Run the pump at all? Or just leave it in its current state until I'm able to devote my time to it?
    I am not disagreeing with imwarren but I think there are a couple of measures you could safely do which, while it may not clear your pool, will certainly help it from getting worse.

    I would suggest you put in 3 large jugs of clorox tonight and then one large jug of clorox each evening until your kit gets in and you can post meaningful test results.

    Absolutely run the pump 24/7 and be prepared to backwash/clean when you get a pressure rise.

    Again, it may not clear your pool but holding it at bay this time of year may be a good idea.

    (your kit shipped today from NC and should be to you on Friday)
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Green Algae

    Thank you, Dave! Not just for the advice, but the great customer service. I will update with my numbers as soon as I can test.

    Jill
    El Paso, Texas
    16x32 Rectangular In-Ground Pool - Plaster - Cartridge Filter - 25,000 gallons - TF100 Test Kit

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    Re: Green Algae

    Got my TF100 on Friday. CYA was 90, so I wasn't putting in nearly enough bleach. Since Saturday morning, I've dumped in over 20 bottles of 182oz 6% bleach and I'm happy to report I've passed the overnight FC loss test and as of yesterday the pool is clear and blue.

    I'm very glad to have found this forum and the BBB method. I'm hoping next season will mean more pool playing and less pool stressing.

    Thanks all!
    Jill
    El Paso, Texas
    16x32 Rectangular In-Ground Pool - Plaster - Cartridge Filter - 25,000 gallons - TF100 Test Kit

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    benavidescj's Avatar
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    Re: Green Algae

    Awesome! Glad you got you algae under control.

    Your CYA is high and should be brought down a bit. Can you post the rest of the numbers?
    Carlos
    Pool: 28,000 gallons IG; IC 40 SWG; Pentair 120 gpm cartridge filter; Marble finish; Pentair Wisperflow 1.5 hp; Polaris 360
    Spa: 350 gallon; Bromine
    How to shock your pool

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    Mod Squad Bama Rambler's Avatar
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    Re: Green Algae

    Glad you got it resolved so easily. Next year it'll be even easier to maintain. The more you do it the easier it becomes. The pool calc will become a reality check instead of a must use. You'll come to know that if your FC reads XX you need to add YY amount of chlorine.

    I agree with Carlos, you need to work on getting your CYA down a bit. Nothing you have to attack immediately but work on it over time.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Green Algae

    Yes - CYA is high. Once the pool was looking less green I drained about 15 inches - equivalent to approximately 4,800 gallons (or 19.2%), which seemed to lower the CYA to about 80-85. CH is also very high (don't have the number in front of me but it was north of 500). According to the pool calc I need to replace 40-50% of the water to get both the CYA and CH down. I will do this over time as I vacuum to waste. I hope to get another two weeks of use out of the pool using my solar blanket and heater. I will re-test everything tomorrow and post all numbers. If I recall correctly, the pH was also high when I initially tested - but that could also be due to the high FC, which I maintained in the 30-35 range while I was shocking the pool.

    Will CYA and CH levels decrease over the winter? Or is water replacement the only way to improve those numbers?

    Jill
    El Paso, Texas
    16x32 Rectangular In-Ground Pool - Plaster - Cartridge Filter - 25,000 gallons - TF100 Test Kit

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    Re: Green Algae

    Hi, Jill,

    Will CYA and CH levels decrease over the winter? Or is water replacement the only way to improve those numbers?
    The answers are sorta' "Yes and yes". Replacement is normally the only way to reduce it but most areas of the country get enough moisture over the winter months to naturally replace quite a bit.

    Usually, the best approach at this time of year is to wait until Spring, test your CYA, and then adjust as necessary
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Green Algae

    I vacuumed to waste on Friday. The pool stayed clear and blue all weekend. Saturday we put the solar cover on. My husband hosed it down first as we hadn't used it in a while and it was dirty. I tested the water Sunday night at 7:30pm:
    FC 29
    CC 2
    TC 31
    pH 7.5
    TA 150
    CH 400
    CYA 85

    I added 182oz of 6% bleach to shock the water because of the CC, left the pump on for 45 minutes after I added the bleach, then turned the pump off for the night. I figured maybe there were some organics on the solar cover that caused the CC number to be high. I tested again this morning (before sunrise) and FC was 33, CC 0.5. The water continues to look crystal clear. Should I now just let the FC level come down on its own? Am I ok to just test the water once daily?

    Jill
    El Paso, Texas
    16x32 Rectangular In-Ground Pool - Plaster - Cartridge Filter - 25,000 gallons - TF100 Test Kit

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    Mod Squad Bama Rambler's Avatar
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    Re: Green Algae

    My personal suggestion (what I would do if it were me) would be to hold the FC up there today and run the OCLT (overnight chlorine loss test) tonight and if you pass it, then let your FC come down to where it needs to be.

    I think there was some organics on the cover that caused th CC and turning the pump off didn't help either but the OCLT will definitely rule out anything else.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Re: Green Algae

    I like bama's ideas.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Green Algae

    Mission: Accomplished. (I think?)

    To recap:
    Sun 9/19 (addes solar cover) @7:30pm - FC: 29.0, CC: 2.0, added 182oz 6% bleach to shock.
    Mon 9/20 @6:00am - FC: 33.0, CC: 0.5. @12:30pm - FC: 30.0, CC: 0, added 182 oz bleach. @7:30pm - FC: 34.5, CC: 0.
    Tue 9/21 @7:00am - FC: 34.5, CC: 0.

    I seem to have passed the OFCL test. So I'll continue to test morning and night and let the FC level come back down to normal. I'm having an end of season pool party this weekend, and I'll have a pretty sparkly blue pool for it.

    Thanks for all your help!

    Jill
    El Paso, Texas
    16x32 Rectangular In-Ground Pool - Plaster - Cartridge Filter - 25,000 gallons - TF100 Test Kit

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