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Thread: Correlation Between Low FC and Low Ph?

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    Join Date
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    Correlation Between Low FC and Low Ph?

    I tried to search for a string on this topic, but I was unsuccessufl. If it has already been addressed, I apologize, and please point me to the discussion. But, is there a link between low FC and low Ph? Over the past couple of days of extremely high heat here on the East Coast, our FC level has been very low in the evenings, and our Ph has been dropping. We've shocked, and the FC comes back up, but by the next evening, it is low. Last night, both FC and Ph were low. I forget the FC level, but it was the lowest level on our test strip, and the PH was 6.4. We shocked with cal hypo and we added 3 lbs of soda ash. This morning, the FC is 20 and the Ph is 8.4. Now, the water is cloudy, but I suspect that is from the cal hypo and maybe even a little undissolved soda ash. Our filter will clear the cloudiness, right? Thanks, in advance, for any adivce you've got!
    Ruth
    21 x 41 Doughboy Desert Spring AGP, 7' Deep, 27,800 Gallons,
    Doughboy 2HP 2-Speed Pump, Cartridge Filter, In-Line Chlorinator

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    Mod Squad JohnT's Avatar
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    Re: Correlation Between Low FC and Low Ph?

    No, there is no correlation. I'd bet that your cloudiness is a result of letting the chlorine drop so low. It's important to maintain the minimum level on the Chlorine CYA Chart at all times.

    The reason you are seeing high pH today is because you have high FC. The pH test is affected by the high chlorine level, so it's difficult to get accurate pH readings while your FC is high.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

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    Mod Squad Bama Rambler's Avatar
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    Re: Correlation Between Low FC and Low Ph?

    It's time for a better test kit also. You need good tests to tell what's going on.
    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: Correlation Between Low FC and Low Ph?

    Thanks so much for the responses! Yes, I have read about the better test kits on this site. We got those test strips with our pool set-up and we thought we'd use those until we run out. But, now I see we need to order that better test kit now!

    One more question - so if the cloudiness after shocking is due to the low chlorine level we had, does that mean we probably had algae or some other organics starting that we just couldn't see? Our water was very clear and sparkly before we shocked and added the soda ash. Thanks, again! I so very much appreicate your help!
    Ruth
    21 x 41 Doughboy Desert Spring AGP, 7' Deep, 27,800 Gallons,
    Doughboy 2HP 2-Speed Pump, Cartridge Filter, In-Line Chlorinator

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    Mod Squad Bama Rambler's Avatar
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    Re: Correlation Between Low FC and Low Ph?

    Without knowing all the test results it's hard to say what it is. It could be algae or calcium or soda ash, or some combination of them all.
    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: Correlation Between Low FC and Low Ph?

    I was just checking out the test kits online. We have a Leslie's Pool Store nearby so I think I should be able to pick up that test kit thsi weekend. It will be interesting to see my real chemical numbers.
    Again, many thanks!
    Ruth
    21 x 41 Doughboy Desert Spring AGP, 7' Deep, 27,800 Gallons,
    Doughboy 2HP 2-Speed Pump, Cartridge Filter, In-Line Chlorinator

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    Re: Correlation Between Low FC and Low Ph?

    Leslie's doesn't normally have the good kits in stock. In particular the critical FAS-DPD for chlorine is missing. The TF100 is a great choice which I heartily recommend.
    20k gallon IGP
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    Mod Squad Bama Rambler's Avatar
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    Re: Correlation Between Low FC and Low Ph?

    While I also recommend just ordering the TF-100, if you do decide to go to Leslies don't let them talk you into less than the K-2006 equivilent. They are bad about telling people that the kits are the same but they're not. It must have the FAS-DPD test not just the DPD test.
    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: Correlation Between Low FC and Low Ph?

    Oh! Thanks for the clarification on the Leslie's product. Maybe I'll order online.
    Ruth
    21 x 41 Doughboy Desert Spring AGP, 7' Deep, 27,800 Gallons,
    Doughboy 2HP 2-Speed Pump, Cartridge Filter, In-Line Chlorinator

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