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Thread: Calcium Hardness, CYA, and TDS Oh My....

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    Red face Calcium Hardness, CYA, and TDS Oh My....

    All,

    My neighbor pointed me to this fantastic site for which I am grateful for. I inherited a pool about a little while ago, went through a shocking process when I found some algee, and now I have tested with my very own test kit for the first time. Below is what I have:

    FC - 9.5 (Assuming still high from the shock)
    PH - 7.6
    TA - 120
    CH - 875
    CYA - 200 (Used 50% pool water, 50% hose water, multiplyied by 2)

    Water readings off the Charts at Leslies...

    I have tons of questions I hope you nice folks don't mind answering
    1. Concerned about CH, I know there is not a magic chemical to reduce this but can I live with this without draning?
    -hose fill water measure 250ppm
    2. CYA incredibly high
    -will this reduce over time?
    -does this have to do with the Muriatic acid I poured into my pool from the shock?
    -can I live with this without draining?
    -during the shock process phosphorous remover was also added, did that cause CYA to go up?
    3. TDS measured 2600 at Leslies, Does my Taylor Test Kit measure TDS or Phosphates?
    4. I have a Pebble Tech surface - should I use a metal big brush instead of nylon?

    Please advise, not sure if draining or reverse osmosis is my only option.

    Thanks,
    Jag

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    Mod Squad jblizzle's Avatar
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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Welcome to TFP!

    To briefly answer your questions.
    1. That is pretty high. You will need to keep the pH in the low 7s to avoid calcium scaling.
    2. No to all questions. This is your biggest issue and you will have to replace water to lower the CYA to take control.
    3. We do not care about TDS. We care about what it consists of, like CH, CYA, salt, etc. Phosphates are also meaningless if you maintain the recommended FC levels, which are a function if your CYA level.
    4. Optional. I use a combo brush now, but nylon is generally fine.
    Jason, TFP Moderator
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    Richard320's Avatar
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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Welcome!

    Draining or reverse osmosis are your only options. Sorry.

    The CH is barely manageable. The CYA is not. At 200 CYA, your minimum FC level should never drop below 15, and target FC will be somewhere closer to 20. Unfortunately, FC above 10 reacts with the pH reagent and affects the readings. So you will never be quite sure of your pH and with CH that high, scaling is almost guaranteed.

    If you plug all your numbers into poolmath it will calculate the CSI. If you start to get in the neighborhood of .5 or above, you're probably going to grow scale in areas with poor circulation. Play with the numbers a little. See what happens when the pH rises. See what happens when CH climbs through evaporation. See what happens when the water gets hotter. You don't have a lot of wiggle room.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    lefty51's Avatar
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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Hello Jag and Welcome , jblizzle is one of the real pros around here and will set you straight. unfortunately the only way to lower CYA and CH is to replace water. But I understand with your water situation in CA, it seems the only real option is reverse osmosis. But it seems to be hard to find and not cheap.

    Also if you could put your pool info in your sig that will help others help you with your situation. Hope that helps.

    Let us know if we can answer any other questions you may have... and again Welcome

    - - - Updated - - -

    I was hoping Richard320 would see this. He is the expert on high CYA in CA
    Si -central Mo. 32' x 16' -- 3'4" to 6' deep Vinyl liner - 16,500 Gals : Triton II filter -Duraglass 2 hp pump - 1 speed : SI-30 salt generator
    TF-100 with speedstir

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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Thanks for the response. Should I lower the PH first or just forget everything and focus on replacing the water? I just don't know how much it would cost, I'm still trying to find some blue prints to figure out how many gallons of water are in my pool. I estimate 10-15k.

    - - - Updated - - -

    Thanks! Any idea what might have caused CH to go up so much? If I replace the pool water with my hose I will have a CH of 250ppm. Is this OK?

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    lefty51's Avatar
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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Quote Originally Posted by Jag View Post
    Thanks for the response. Should I lower the PH first or just forget everything and focus on replacing the water? I just don't know how much it would cost, I'm still trying to find some blue prints to figure out how many gallons of water are in my pool. I estimate 10-15k.
    If you know width, length and average depth of your pool, POOLMATH can calculate the gallons for you
    Si -central Mo. 32' x 16' -- 3'4" to 6' deep Vinyl liner - 16,500 Gals : Triton II filter -Duraglass 2 hp pump - 1 speed : SI-30 salt generator
    TF-100 with speedstir

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    Re: Calcium Hardness, CYA, and TDS Oh My....

    I though I did upate my signature, I'll check agaim:

    10-15K Gallon Pool
    IG
    DE Filter, Hayward
    Pump Model? 2-speed (2HP)
    2004 Built Pool
    Taylor K-2006 Test Kit
    SWG dead, not being used (Would like to someday replace and use)
    Fill Pool With Hose, CA water restrictions

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    Richard320's Avatar
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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Quote Originally Posted by Jag View Post
    Thanks for the response. Should I lower the PH first or just forget everything and focus on replacing the water? I just don't know how much it would cost, I'm still trying to find some blue prints to figure out how many gallons of water are in my pool. I estimate 10-15k.

    - - - Updated - - -

    Thanks! Any idea what might have caused CH to go up so much? If I replace the pool water with my hose I will have a CH of 250ppm. Is this OK?
    Even if all you do is replace half the water, you'll be in a much better position.

    Tap water has no CYA in it, so whatever percentage of water you replace, CYA will drop the same amount. Caution: even diluted 1:1 and getting 200 doesn't mean you can't be at 240 CYA. That's where I started when I assumed control. The scale graduations get awful close together down there near the bottom.

    The CH is a bit trickier. Convert percentages to decimal. (.5*875) +(.5*250) = 562 CH. Much better.

    You don't have to do it all at once, although that is the most efficient way. If you drain off 3" at a time and use it on the lawn (If you have any lawn left) you can use the irrigation water you don't need to refill the pool. That's how I did it, and it was a glorious day when we finally had a rainstorm during that first year. I aimed a downspout at the pool and used the spa as a settling basin and replaced a bunch of water. Things were much easier after that.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Quote Originally Posted by Richard320 View Post
    Even if all you do is replace half the water, you'll be in a much better position.

    Tap water has no CYA in it, so whatever percentage of water you replace, CYA will drop the same amount. Caution: even diluted 1:1 and getting 200 doesn't mean you can't be at 240 CYA. That's where I started when I assumed control. The scale graduations get awful close together down there near the bottom.

    The CH is a bit trickier. Convert percentages to decimal. (.5*875) +(.5*250) = 562 CH. Much better.

    You don't have to do it all at once, although that is the most efficient way. If you drain off 3" at a time and use it on the lawn (If you have any lawn left) you can use the irrigation water you don't need to refill the pool. That's how I did it, and it was a glorious day when we finally had a rainstorm during that first year. I aimed a downspout at the pool and used the spa as a settling basin and replaced a bunch of water. Things were much easier after that.
    Thanks for all of the information. It doesn't sound like I can play with my pool chemistry much and may even be dangerous to try to lower the pH. I also don't have much of a lawn but what I will do is look into some reverse osmosis pricing tomorrow.
    BTW - According to the water balance calculator that came with my Taylor kit my Saturation Index measures 0.7 (I will compare it with the tool on-line)

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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Quote Originally Posted by Jag View Post
    Thanks for all of the information. It doesn't sound like I can play with my pool chemistry much and may even be dangerous to try to lower the pH. I also don't have much of a lawn but what I will do is look into some reverse osmosis pricing tomorrow.
    BTW - According to the water balance calculator that came with my Taylor kit my Saturation Index measures 0.7 (I will compare it with the tool on-line)
    Per the City, I will not be able to drain/fill my pool until October. Just tested today:
    FC=11
    PH=7.8

    Didn't bother testing CH & CYA as they are really high.

    What can I do in the mean time?

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    Mod Squad jblizzle's Avatar
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    Re: Calcium Hardness, CYA, and TDS Oh My....

    All you can do is try to figure out just how high the CYA is and then keep your FC really high ... of course then you can not test the pH when the FC > 10ppm.

    Or just do a lot of really small water changes ... or pay for the RO.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

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    Re: Calcium Hardness, CYA, and TDS Oh My....

    Quote Originally Posted by jblizzle View Post
    All you can do is try to figure out just how high the CYA is and then keep your FC really high ... of course then you can not test the pH when the FC > 10ppm.

    Or just do a lot of really small water changes ... or pay for the RO.
    I will keep the FC high. Someone recommended an acid wash once I drain the pool, is that necessary? I can't tell, will add some pics. The surface is pebble tech.

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