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Thread: CYA high, PH low, chlorine low...new to pools...please help

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    CYA high, PH low, chlorine low...new to pools...please help

    I had a pool maintenance service for the past 4 years and now trying to care for my pool myself. Here is where I'm at on day one:

    CYA at 140ppm
    Chlorine levels low but there are about 6 tabs in my auto-chlorinator
    Tested for total alkalinity but my Taylor test skipped green and went straight to red
    Taylor test also showed low ph
    Couldn't get a good reading on calcium hardness
    Recently had some heavy rain....drained the pool to about mid skimmer level
    Pool looks clean but a little cloudy

    I have a 21x38 free form vinyl pool...3' in shallow end, 8' in deep end...about 33,000 gallons
    Pentair Clear Plus filter system
    Polaris 380
    Pentair auto-chlorinator

    I have a good work ethic and ready to tackle this but need some advice from someone other than my previous pool maintenance company or the folks at the pool store...getting too much conflicting information!

    What can I do to lower CYA, raise chlorine, level out Ph and address whatever issue is causing the TA test to go straight to red.
    21x38 free form vinyl, pentair whisperflo, pentair clean clear plus, polaris 380

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    Mod Squad jblizzle's Avatar
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    Re: CYA high, PH low, chlorine low...new to pools...please h

    Welcome to TFP!

    You need to replace a lot of water to lower the CYA down to between 30-50ppm.

    Then stop using the tablets are causing all your problems. They are driving the CYA up. And driving the pH and TA down. You need to switch to liquid chlorine.

    You can gain a lot out knowledge by reading Pool School (button at upper right of the page)
    Jason, TFP Moderator
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    Re: CYA high, PH low, chlorine low...new to pools...please h

    Welcome to TFP!

    When the Total Alkalinity (TA) test goes straight to red, that means the pH is 4.5 or lower which is very bad. The continued use of Trichlor tabs lowered the pH and the TA to the point where the TA was used up and the pH then crashed. You would add pH Up (Arm & Hammer Super Washing Soda; careful: NOT the laundry detergent) to increase both pH and TA. However, you will also need to do a partial drain/refill to lower the CYA level -- figure a 50% drain/refill at least, probably 60%. You may need to do multiple partial drain/refill as you don't want to drain below leaving about 1 foot in the shallow end of the pool.

    Get those tabs out of your auto-chlorinator since they are just making things worse by increasing the CYA level and lowering the pH and TA. Use chlorinating liquid or regular unscented bleach (NOT splash-less or outdoor).

    It's practically unbelievable that your previous pool maintenance company didn't keep the TA up and let the pH crash. You might have corrosion in your gas heater (if you have one), especially if it's got a copper heat exchanger (at least with a vinyl pool the risk for metal staining is lower).
    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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    Re: CYA high, PH low, chlorine low...new to pools...please h

    Thank you so much chemgeek and jbizzle...I'm about to go to work to get this pool in order. I saw on previous posts that a fountain can help keep ph levels up....would that be a good investment once I get things in order.
    21x38 free form vinyl, pentair whisperflo, pentair clean clear plus, polaris 380

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    Re: CYA high, PH low, chlorine low...new to pools...please h

    No, you should not need a fountain because you should stop using Trichlor tabs or at least minimize their use. If you were to keep using Trichlor, then you would keep the pH stable by adding pH Up regularly (pH Up is sodium carbonate and is the same as Arm & Hammer Super Washing Soda). That raises both the pH and the TA and with a higher TA the pH won't drop as fast. Yes, aeration will help keep the pH up, but you'd still have to add a chemical product to restore the TA since that would drop. There is no way to be able to use Trichlor alone without adjusting at least TA if not pH and Trichlor increases the CYA level over time.

    When you use chlorinating liquid or bleach as your primary source of chlorine, then you want to minimize aeration sources (spillovers, waterfalls, fountains, etc.) since they will tend to make the pH rise.

    By the way, the very low pH could also have damaged your vinyl liner -- first symptom might be wrinkling. Let's hope not.
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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    Re: CYA high, PH low, chlorine low...new to pools...please h

    Great thanks for the info! I want to start using the BBB method to care for my pool. However, I have to say I am nervous about putting in bleach. My pool is draining now and after I do a couple drain/refills, I'm sure I'll have to put about 7 or 8 gallons of bleach in my water, along with the Arm and Hammer Super Washing Soda. I assume it's safe because it sounds like you're very schooled on this subject. So how long should I wait before testing and letting my kids back in the pool? Thanks again for your help!
    21x38 free form vinyl, pentair whisperflo, pentair clean clear plus, polaris 380

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    Re: CYA high, PH low, chlorine low...new to pools...please h

    It might be helpful to look at this pool school article: http://www.troublefreepool.com/pool-..._chlorine_pool

    Bleach ( assuming non scented, and not the "splashless") is just weaker liquid chlorine that you can buy at the pool store. Both have the active ingredient Sodium Hypochlorite. Same active ingredient difference concentrations. Typically 65 or 8.25% for bleach and 10% or 12.5% for Liquid Chlorine.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Re: CYA high, PH low, chlorine low...new to pools...please h

    Thanks all, I got my pool on the road to recovery. Partially drained and refilled twice got my CYA down to 70, TA is up to 90 from 0, and Ph is up to 7.2 from 6. I like this BBB method...dumped the pucks out of my auto chlorinator and bought a bunch of beach, baking soda, and borax. Thanks again!
    21x38 free form vinyl, pentair whisperflo, pentair clean clear plus, polaris 380

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    Re: CYA high, PH low, chlorine low...new to pools...please h

    You probably won't need the baking soda much if at all and probably won't use the borax either unless you were adding borates. BBB doesn't mean using those three chemicals. They are just examples of chemicals you can buy at a grocery store instead of a pool store. Mostly you will likely use bleach (or chlorinating liquid) and some Muriatic Acid.
    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
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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