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Thread: low pH and alkalinity

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    low pH and alkalinity

    Hello! I'm getting an early start on opening my pool. I tested the water this evening (pump is not hooked up yet) and these are the results:
    FC 1.5
    CC 0
    pH 7.2
    Alk 50
    CYA 50
    I use the test kit recommended by this site. My question is, do I want to fix the pH first by adding soda ash and hope that it fixes the alkalinity or add baking soda to increase alkalinity and hope that if fixes the pH. OR wait until I've had the pump up and running for a bit and then test?
    Is it important to bring up FC first or balance pH?
    Thanks.
    26,000 gallon 33 foot round AG pool, cartridge filter, 175 SQ FT ECCO ELMNT FILTER 1.5 HP 2 SPEED, Southeastern IN

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    JasonLion's Avatar
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    Re: low pH and alkalinity

    Wait until the pump has been running for at least an hour, then retest.

    If the test happens to be exactly the same, raise the TA to around 70 and let the PH take care of it's self (it will most likely go up on it's own, if only very slowly).
    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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    Divin Dave's Avatar
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    Re: low pH and alkalinity

    Hi Shellspool.
    Pool Math has a cute feature at the bottom called Effects of Adding... you can see whats going to happen before you do it!

    in your 26K gallons...adding 75 ozs of Soda Ash or Washing Soda will raise your TA to 70 and your Ph to about 7.9. Then use muriatic acid to bring the Ph down a tad if you want to.

    I would say Add chlorine first, and then follow that up with some soad ash then MA if you want to lower the Ph a tad.

    hope this helps!
    Divin Dave,
    IG Vinyl, 15' x 30', 3 1/2' - 6' deep, Oval, ~15K gal, Intelliclor IC40, Intelliflo VS pump, Clean and Clear 420 Filter, auto-fill-disabled, Retrofit LED Color Light, Dolphin Nautilus Robot, TF100 Test Kit, Taylor K1766 Salt Test Kit, Tftestkit Pressure Gauge.
    www.tftestkits.net Experience- it's what's learned just after you needed it most !!

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    Re: low pH and alkalinity

    Can I use baking soda and get the same results?
    26,000 gallon 33 foot round AG pool, cartridge filter, 175 SQ FT ECCO ELMNT FILTER 1.5 HP 2 SPEED, Southeastern IN

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    JasonLion's Avatar
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    Re: low pH and alkalinity

    I would definitely start with baking soda. That will mostly raise the TA, and perhaps bump up the PH just a tiny bit. PH at 7.2 is already acceptable, if not ideal. So much more important to raise TA than PH.
    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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    Re: low pH and alkalinity

    Wait until the pump has been running for at least an hour, then retest.
    Very important!!!
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: low pH and alkalinity

    Ok, so I drained my pool halfway and have refilled. My total alkalinity was high so I added acid. Now my alkalinity is 110 but my pH is 6.7. How do I raise the pH without affecting the alkalinity?
    26,000 gallon 33 foot round AG pool, cartridge filter, 175 SQ FT ECCO ELMNT FILTER 1.5 HP 2 SPEED, Southeastern IN

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    Mod Squad tim5055's Avatar
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    Re: low pH and alkalinity

    Quote Originally Posted by Shellspool View Post
    Ok, so I drained my pool halfway and have refilled. My total alkalinity was high so I added acid. Now my alkalinity is 110 but my pH is 6.7. How do I raise the pH without affecting the alkalinity?
    Pool School is a wonderful tool. From Pool School
    Raising PH

    PH can be raised in three ways: borax, soda ash, and aeration. Borax is usually the best choice. Borax raises the PH and also raises the TA level just a little. If your TA level is low soda ash will raise both the PH and TA levels. If your TA level is high, aeration is best as it will not raise the TA level at all. However, aeration is rather slow compared to the other two.

    Borax is available as 20 Mule TeamŪ Borax Natural Laundry Booster. It is sold in the laundry detergent section of most larger grocery stores and some big box stores. Borax is best added by pre-dissolving it in a bucket of water and then pouring that slowly in front of a return.

    Soda ash is available as ARM & HAMMERŪ Super Washing Soda Detergent Booster. Do not confuse this with ARM & HAMMERŪ laundry detergent! It is sold in the laundry detergent section of most larger grocery stores and some big box stores. It is also sold by pool stores under various names, including PH Increaser, PH Up, Balance Pak 200, etc. Soda ash is best added by pre-dissolving it in a bucket of water and then pouring that slowly in front of a return.

    Aeration can be provided by a SWG, spa jets, waterfall, fountain, return pointed up so it breaks the surface, air compressor, kids splashing, rain, etc. It can take some time for aeration to raise the PH. The higher your TA level, the faster aeration will work.
    6.7 is at the low end of testing, so it may be lower. You need to use Borax to get it up to a reasonable number. Then you can run through several acid/aeration cycles to work the TA down
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: low pH and alkalinity

    Thanks! You were quick to answer! I was just getting ready to reply that I found the answer in the section "how to lower alkalinity". Sometimes I feel like I'm looking for a needle in a haystack when trying to find the answers to my questions.
    Thanks again!
    26,000 gallon 33 foot round AG pool, cartridge filter, 175 SQ FT ECCO ELMNT FILTER 1.5 HP 2 SPEED, Southeastern IN

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    Mod Squad tim5055's Avatar
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    Re: low pH and alkalinity

    Quote Originally Posted by Shellspool View Post
    Thanks! You were quick to answer! I was just getting ready to reply that I found the answer in the section "how to lower alkalinity". Sometimes I feel like I'm looking for a needle in a haystack when trying to find the answers to my questions.
    Thanks again!
    I'm glad you found it.

    Right now you need to get that pH up as we don't know how low it really is.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: low pH and alkalinity

    Well I have a pound of pH plus (sodium carbonate) here. Can I use that? I also just pointed the return up so there is a break in the surface of the water.
    Thanks again for your help.
    26,000 gallon 33 foot round AG pool, cartridge filter, 175 SQ FT ECCO ELMNT FILTER 1.5 HP 2 SPEED, Southeastern IN

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    Mod Squad pooldv's Avatar
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    Re: low pH and alkalinity

    Here is an overview of pool chemicals that will help. Recommended Pool Chemicals
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    Mod Squad tim5055's Avatar
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    Re: low pH and alkalinity

    Quote Originally Posted by Shellspool View Post
    Well I have a pound of pH plus (sodium carbonate) here. Can I use that? I also just pointed the return up so there is a break in the surface of the water.
    Thanks again for your help.
    That is going to raise the TA much more than Borax, making it a little harder later to bring the TA back down.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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