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Thread: Pool turned green after backwashing! HELP PLEASE

  1. Back To Top    #1

    Join Date
    Jun 2016
    lost creek

    Pool turned green after backwashing! HELP PLEASE

    Hi so iam a new pool owner. We opened our pool and had it almost clear and my husband and daughter swam in it. That night we had a heavy storm and woke up to it neon bright green. We bought some shock with algae killer in it and put 3 lbs in it. The next morning it looked even worse!! At the time we didn't have any extra money to do anything so we waited a week ( so by now its dark green with tadpoles looking like a swap lol). This time i found some liquid chlorine pretty cheap so i bought 4 gallons. That night i put 2 gallon in the pool. The next morning it was light green instead of dark. I am thinking awesome this is working so that night i put the other 2 gallon in. Woke up the next morning to it being blue cloudy water. I tested it and it said the alkalinity and ph was low. I read that i could baking soda so i bought a 12 lbs bag and put it in there yesterday. woke up this morning and u could finally see the bottom. I noticed there was some green spots on the bottom , a lot in the middle, and assumed its algae. We back washed it and then went out in about an hour and put 2 more gallon of liquid chlorine in it ( cause the strips say everything but chlorine is fine) and it was green again. Just by back washing it! thought i was finally on my way to a swimmable pool but now i am so dishearted i might just call it quits. Please someone help me but also remember i am new to this so i don't know as much as most.
    Above ground oval pool , sand filter, 30,000 gallon, first time pool owner

  2. Back To Top    #2
    Mod Squad pooldv's Avatar
    Join Date
    Aug 2012
    DFW, TX

    Re: Pool turned green after backwashing! HELP PLEASE

    Welcome to TFP!

    Well, the pool store is not helping so let's stop going there. TFP is all about testing your own water with a good test kit and only adding what you need in your pool.

    I use the TF-100 from You will need the XL option so you have enough tests to kill the algae.

    When you get the test kit post some test results and get ready to follow this process to kill the algae, SLAM

    While you are waiting for the test kit to arrive brush the pool daily and add 1-1/2 jugs of plain, unscented concentrated bleach, 8.25%.

    To better understand how TFP works do some reading in Pool School.
    Start here, ABCs of Pool Water Chemistry
    and then here, Pool School - Getting Started
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  3. Back To Top    #3

    Join Date
    Sep 2015
    Rome, NY

    Re: Pool turned green after backwashing! HELP PLEASE

    Also, knowing your true number of gallons will help.
    I have a 30' radiant and it is less than 22k.
    Are you sure yours is 30k?
    Pool installed 8/2015. 30' round Radiant pool. 21,000 gallons. 200# sand. Hayward Vari flow XL valve. 1.5hp Hayward Power-Flo Matrix running 10 hours/day in two periods. TF100 with speed stir. Sun all day, south side of house
    Order test kit TF-100 w/ Speed Stir and then Poolmath Calculator --- RECOMMENDED LEVELS --- POOL SCHOOL --- Algae? --- Chlorine/CYA CHART.

  4. Back To Top    #4

    Re: Pool turned green after backwashing! HELP PLEASE

    I agree, 30,000 gallons is unlikely for an above ground pool. What are the dimensions including depth?

    The green might be iron. Try some ascorbic acid (vitamin C) on a test spot to see if it cleans the liner.
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  5. Back To Top    #5

    Join Date
    May 2015
    Land O Lakes, FL

    Re: Pool turned green after backwashing! HELP PLEASE

    Trust these guys and gals, do everything they said, then you will not want to give up. These methods are as much of a guarantee as you will get to have a sparkling pool. Take pictures along the way.
    2016 Pool Build: 12k IG Blue Granite Pebblesheen, Travertine Coping & Pavers, Pentair IntelliFlo, Intellichlor, Easytouch, Clean & Clear 320, Heliocol Solar - TF-100 test kit w/ SpeedStir
    SWG Run Time Calculator

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