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Thread: Low chlorine level and green tint

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    Low chlorine level and green tint

    I have a 26000 gallon inground vinyl liner pool that I opened last weekend. I essentally did the same things that I have done for the past couple of years which is to check the ph, shock using a powdered chlorine shock vacuumed etc.

    After a couple of days, the water still looked a little green. It was clear, but the pool looked green instead of blue.

    I took a water sample to my local pool store, and the results were all good except the FC. They told me I was good to go and that I just needed to shock it.

    Over the past week, I've probably added 10 pounds of powder shock and I still had no FC reading and the green tint did not go away.

    After some searching on google, I came accross this GREAT forum and read up on using bleach to raise the chlorine level. I used the Pool Calculator and it told me to add 6 182oz bottles of bottles of bleach. I did this and waited a few hours an checked the levels. My FC is now around 2.

    Right now these are the levels that I can test...

    FC = 2
    TH = 100
    PH = 7.4
    TA = 180
    CA = 40

    My questions are...

    How long should it take for the bleach to affect the FC level?

    and

    Am I on the right track with the green tint?

    I would like to thank everyone on this forum that provide such a wealth of information!!!

    Sean
    17x35 Inground Vinyl Liner
    26,000 Gallons
    Nautilus DE Filter
    Pacfab Challenger Pump

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
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    The bleach already raised the chlorine, then the algae consumed it. You need to raise it again.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

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    duraleigh's Avatar
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    Sean,

    You have an algae bloom and it is going to consume a LOT of chlorine to get yoyur water clear. As John said, you need to bring the FC back up and HOLD IT THERE to get rid of the green.

    First chance you get, post a test result for CYA...that may be influencing your chlorine loss.
    Dave S. - Forum owner
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  4. Back To Top    #4

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    Quote Originally Posted by duraleigh
    Sean,

    You have an algae bloom and it is going to consume a LOT of chlorine to get yoyur water clear. As John said, you need to bring the FC back up and HOLD IT THERE to get rid of the green.

    First chance you get, post a test result for CYA...that may be influencing your chlorine loss.
    How long should I wait before I test after adding more chlorine?

    Also, the CYA is 40......I listed it as CA above.

    Thanks again.

    Sean
    17x35 Inground Vinyl Liner
    26,000 Gallons
    Nautilus DE Filter
    Pacfab Challenger Pump

  5. Back To Top    #5
    Mod Squad JohnT's Avatar
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    Don't bother testing after you add IF you know the volume of your pool accurately enough to feel comfortable with your calculation. By the time the chlorine is circulated enough to be measured, so much of it has been consumed that you will have less than you should. Add enough to reach shock level, then test it an hour later, and add enough to reach shock level again. With algae, the chlorine can all be gone in 4 hours, so hit it every hour until it holds most of the chlorine for an hour, then drop back to every 4 hours, then every 8 hours as it holds most of the chlorine between tests.

    Make sure to read this sticky: How to turn your green pool back into a sparkling oasis

    Remember, it's the consistent high chlorine level you need, so the frequent testing and adding chlorine is the key.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  6. Back To Top    #6

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    Well, I've added quite a bit of bleach, and it looks like the FC level is finally going up.

    Hopfully it doesn't take much more. I've hit up all the local stores for the large jugs of bleach!

    Thanks for your help.

    Sean
    17x35 Inground Vinyl Liner
    26,000 Gallons
    Nautilus DE Filter
    Pacfab Challenger Pump

  7. Back To Top    #7

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    I was using test strips to check my water and they were pretty close to the results I was getting at my pool store that I posted below, so I figured they were at least ok.

    I tested again today and had what seemed to be low ph, and low cya so I bought an Aqua Chem test kit at Sears.

    Here are the numbers that I got with the kit

    FC=1.0
    TC=1.5
    PH=<6.8
    TA=90
    CYA=0 (I can clearly see the black dot with the vial full)

    While it seems strange that the PH and TA would be that much lower in a few days, I don't understand why the CYA is now reading 0? Four or five days ago my test strips and the local pool store both showed ~40 and now my test strips and the Aqua Chem black dot test are both showing 0.

    From what I've read on this site, the only ways for CYA to go down are through removing water from the pool.

    Am I missing something?

    Sean
    17x35 Inground Vinyl Liner
    26,000 Gallons
    Nautilus DE Filter
    Pacfab Challenger Pump

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