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Thread: Lowering pH while adding CYA and shocking

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    Lowering pH while adding CYA and shocking

    I need to lower the pH add CYA and shock because of algae due to not using chlorine because of 2 major leaks. I got the leaks fixed and now I need to adjust.

    The pH is 8.0 because of the fill waters pH. I need to get the CYA to 30 and I'm not sure where I should lower the pH to.

    I have two factors that may influence what I want to lower the pH to. I want to use two pool misters for 2-4 days depending on how well they work. They will be on a 1750 rpm for most of the time, but I was planning on increasing them to 2500 the speed I usually run the cleaner with for a few hours during the coldest part of the night because it works better than.

    I'm also planning on using 1-inch tri-chlor until I run out because I hate wasting and that will lower the pH. With those two things....I'm not sure where I should get the pH to.

    I don't know how much the Aeration will increase and I'm not clear on how fast Tri-Chlor lowers the pH. When I had the Chlorine level didn't seem to stay up while using the pucks...I think because of the leak. Since I've fixed the leaks it should hold and effect the pH more.

    Also how should I go about adding CYA and Dry Acid which is what I have. I have pH minus which I think is the same thing no MA. pH minus or dry acid is the same as the dry acid on the pool calculator is that correct?

    Do I add CYA or Acid first and how long in between. Also I'll need to shock the pool....which I'm thinking would be the last thing after adding the stabilizer and the acid...but I'm not sure.

    Thanks
    Lewisville, Texas 22,000 Gallon IG Plaster Chlorine FNS Plus Vertical Grid D.E. Filter 60 sq. ft. 150 GPM Push/Pull Valve Hayward Ecostar SP3400VSP Baracuda Zodiac G3 Cleaner

    Caldera Vacanza Marino Vanto Spa VMA4R6393

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    JasonLion's Avatar
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    Re: Lowering pH while adding CYA and shocking

    What are your current chemical levels? Everything starts with knowing where you are.

    Also, just want to make sure we are not dealing with freshly applied plaster?
    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: Lowering pH while adding CYA and shocking

    Quote Originally Posted by JasonLion
    What are your current chemical levels? Everything starts with knowing where you are.

    Also, just want to make sure we are not dealing with freshly applied plaster?
    No fresh plaster. Why that question did I say something that made it sound like I might have freshly applied plaster? The leaks? They were in the pipes. One behind the skimmer nearest to the pump and one behind the return that is near that.

    FC is 0 pH 8.0 TA is 100-140 Its hard to tell I have crappy Aquacheck Select Strips...never buying those again. I don't want to bother with the chemical kits that I have to use reagents for...but that set of strips is horrible. The color differences are hard to distinguish. The Leslie's test strips I had before were much more legible.

    CH is 260, CYA 0 Borate 0 Salt 0
    Lewisville, Texas 22,000 Gallon IG Plaster Chlorine FNS Plus Vertical Grid D.E. Filter 60 sq. ft. 150 GPM Push/Pull Valve Hayward Ecostar SP3400VSP Baracuda Zodiac G3 Cleaner

    Caldera Vacanza Marino Vanto Spa VMA4R6393

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    JasonLion's Avatar
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    Re: Lowering pH while adding CYA and shocking

    Alright. The "normal" approach would be:
    1) Lower the PH to around 7.2 to 7.4
    2) Start raising CYA to 30
    3) Add chlorine

    However, if you want to you can combine all of those steps into one and simply use trichlor to have all three effects. The only issues with using trichlor are that the CYA will only come up slowly, so you will tend to have FC go to zero anytime it is sunny, and you don't want to continue using trichlor for too long, as CYA will eventually get too high. You can compensate for that by adding perhaps 15 to 20 ppm of CYA separately.
    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: Lowering pH while adding CYA and shocking

    Quote Originally Posted by JasonLion
    Alright. The "normal" approach would be:
    1) Lower the PH to around 7.2 to 7.4
    2) Start raising CYA to 30
    3) Add chlorine

    However, if you want to you can combine all of those steps into one and simply use trichlor to have all three effects. The only issues with using trichlor are that the CYA will only come up slowly, so you will tend to have FC go to zero anytime it is sunny, and you don't want to continue using trichlor for too long, as CYA will eventually get too high. You can compensate for that by adding perhaps 15 to 20 ppm of CYA separately.
    How fast will the Trichlor lower pH without anything aiding it? It depends on how much Trichlor I have to use I guess...so I guess there isn't a way to know. Guess I'll just have to monitor it with the strips and see if its going down too fast or not enough.

    If I use Dry acid to lower the pH how long do I need to wait before adding CYA? Is there a rule of thumb on how long to wait in between different sets of chemicals? Perhaps having to do with allowing them to mix well...no clue how long that takes though.
    Lewisville, Texas 22,000 Gallon IG Plaster Chlorine FNS Plus Vertical Grid D.E. Filter 60 sq. ft. 150 GPM Push/Pull Valve Hayward Ecostar SP3400VSP Baracuda Zodiac G3 Cleaner

    Caldera Vacanza Marino Vanto Spa VMA4R6393

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    JasonLion's Avatar
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    Re: Lowering pH while adding CYA and shocking

    An hour is plenty of time. An hour is nearly always enough time to wait for almost any pair of chemicals, though there are a few exceptions.
    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: Lowering pH while adding CYA and shocking

    Quote Originally Posted by JasonLion
    An hour is plenty of time. An hour is nearly always enough time to wait for almost any pair of chemicals, though there are a few exceptions.
    Thanks much
    Lewisville, Texas 22,000 Gallon IG Plaster Chlorine FNS Plus Vertical Grid D.E. Filter 60 sq. ft. 150 GPM Push/Pull Valve Hayward Ecostar SP3400VSP Baracuda Zodiac G3 Cleaner

    Caldera Vacanza Marino Vanto Spa VMA4R6393

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