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Thread: Low Ph and disappearing chlorine

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    Low Ph and disappearing chlorine

    Help, please..... I have almost successfully won the war on yellow algae (Yellow Treat), but my ongoing problem is my Ph won't increase above 7.2 (adding soda ash). My chlorine is disappearing as fast as I add it (3 gal liquid). My pool is approx 12,000 gallons. Temps have been in the high 90's.
    Does anyone have any thoughts. Thank you!!!!!!!!![/size]
    cbisquit

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    Welcome to TFP!

    post a full set of numbers and we can help you.

    Sounds like you still need to be waging war on the algae. You can successfully treat yellow or mustard algae with bleach (liquid chlorine) but you must know your CYA. Bleach is more effective at lower pH anyway, so I would not be terrible worried about that right now, unless it goes lower.

    Jason's calculator in my sig can help you find how high you need to shock to kill the mustard. Get your numbers and post back.

    8200 gallon 20' x 48" round vinyl frame pool, manually chlorinated with 10% liquid, salt added to ~2000, 12" sand filter, 1600gph pump, TF100 test kit
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    JasonLion's Avatar
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    Yellow Treat will consume large amounts of chlorine before the chlorine level will stabilize again. Once you add Yellow Treat you need to keep feeding it chlorine as fast as possible until you can hold a chlorine level again. In the process it should kill just about anything that might be living in your water, but it can be quite a pain.

    I'm less sure about the PH issue, but I suspect it will settle down once the Yellow Treat is done.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    The Yellow Treat product from United Chemical says "Proprietary" for its ingredients but the PAN Pesticides Database says it's 88.8% Sodium Bromide. So chlorine will get consumed converting the bromide to bromine (hypobromous acid). Though effective against algae, and specifically yellow/mustard algae, I don't know if it's as effective against all other pathogens. Generally, it is a little weaker than chlorine against bacteria and viruses, but those are mostly easy to kill or inactivate anyway.

    One of Ben's tips here says that eventually bromide will get broken down in sunlight if dimethyl hydantoin is not present (this is the typical delivery of bromine in spas). However, I can't seem to find any reasonable reaction for getting rid of the bromide in the water even under sunlight. I do see that hypobromous acid, like hypochlorous acid, can outgas and will likely do so much more quickly since it does not attach to CYA, so perhaps that is how it ultimately dissipates (though I would expect something similar to happen in spas which would result in a bromine smell).
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
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    Thanks to all for your replies,
    I will gather my numbers and repost. I did learn from the pool supply store that Yellow Treat will eat my chlorine VERY quickly. Is there a preference on using dry chlorine vs. liquid chlorine? I have also put 2 3" chlorine tabs in the floater thinking this would help sustain the chlorine.

    Also, I was told I should put the soda ash into a bucket (water 1st) then add to the deep end, is this correct? If so I've been doing it wrong, but I don't think that would keep my Ph from increasing do you?

    Thanks again to all!!!!!
    cbisquit

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    JasonLion's Avatar
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    Disolving the soda ash in a bucket before adding it to the pool is the right way to do it. That wouldn't have caused any problems.

    Each kind of chlorine has advantages and disadvantages. Liquid chlorine doesn't add anything you don't want to your pool. The tablets/pucks and some of the powders add CYA, and other powdered chlorine adds calcium. But liquid chlorine is a bit more work to transport.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    .....and less expensive too.
    cbisquit

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    Bet you thought I disappeared... I tested my water again and my numbers are:
    Chlorine 0.2 (added 3 gallons yesterday)
    Ph 6.8 - 7.2
    Alk 130
    Conditioner 100

    Still not holding the chlorine I added yesterday and the 2 tabs I placed in the floater don't seem to be adding anything. I did add 14oz of soda ash mixed with water into the deep end. I'm thinking if my ph comes up that will help my chlorine stabilize????

    Ideas????

    Thank you again~~
    cbisquit

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    JasonLion's Avatar
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    You need way more chlorine. The Yellow Treat is going to continue to consume chlorine for a while.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    If 'conditioner' is 'stabilizer' or CYA, be careful about which chlorine tabs you're using. If its 'stabilizer' (CYA) and you're at 100 now you don't want any more.

    What kind of tabs are you using, and is 'conditioner' stabilizer or CYA?

  11. Back To Top    #11

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    Hey JasonLion,
    All is good today. Added more chlorine last night. My ph, chlorine and CYA levels are good as well. I'll keep an eye on them but my numbers have been good all day!

    Thanks agaion for your insight!
    cbisquit

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