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Thread: Pool out of whack, help needed

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    Pool out of whack, help needed

    Life got in the way these last couple of weeks and I ended up letting my pool go a bit. Bad timing, because it's springtime in Texas and with all the pollen and organics, it quickly got out of whack. A couple of days ago, I saw that one side of the pool had started getting a yellow green coat of algae. Due to time constraints I gave it a brushing and 3 gallons of 10% liquid chlorine to raise FC to shock levels.

    Today I got to inspect the pool more carefully. The yellow green coat was back but brushed off easily. There was also some green algae spotting in various places. Here are the readings for my 30kgal pool:

    pH: 8.4
    FC: 0
    CC: 0
    TA: 90
    CYA: 20

    I have started a SLAM (unfortunately before checking pH, or I would have adjusted that to 7.3 first). Is it still OK to raise pH midway through the SLAM?

    For one, CYA has been super low all winter. Would trichlor pucks be the best way to raise CYA to say 40 in my situation? Should I wait till after the SLAM to raise CYA?

    What about the algae stains and spotting? Would brushing the walls be enough or should I do anything else besides the SLAM (backwash filter, clean behind lamps, etc.)

    Thanks for reading and offering advice!







    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Texas Splash's Avatar
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    Re: Pool out of whack, help needed

    Hey Houston! I would leave CYA at 20 until after the SLAM to save you on some bleach. Raise it up after you pass all 3 criteria. As for the stubborn spots, just continue to brush a few times daily and follow everything else listed on the SLAM page (pump 24/7, clean filter, etc). Of course maintain that SLAM/shock FC of 10 based on a CYA of 20. Today's wind (at least in our area) was brutal today. It looks like someone cut their lawn and dumped it on our pool.

    No sweat, the SLAM will fix it. If you still think you have stains or yellowing after passing the 3 SLAM criteria, let us know. Oh, and as for the pH .... well, your SLAM FC shock is only 10, so if you let it come to about an FC of 9 real quick, you can test pH and adjust to the 7.2-7.5 range, then kick-up FC to 10 again.

    After the SLAM, yes, you can use the pucks if you want, just keep an eye on the CYA.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
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    Re: Pool out of whack, help needed

    When FC is below 10 during one of your checks, test pH and fix it. Just add the acid and grab the brush and make a quick lap around the pool. Then resume the SLAM.

    You want to keep the CYA level down around 30 or so while SLAMming, if possible, because that keeps the target FC lower while still protecting the CYA from sunlight losses.

    You can use dichlor or trichlor to raise CYA while you chlorinate, but they are both acidic, so you'll be juggling three parameters at once if you try that. Effects of Adding Chemicals at the bottom of poolmath will show you what each chemical does. Note the pH change is an estimate, and the more you try to add, the farther from reality it becomes. Which is a longwinded way to say I wouldn't rely on pucks to raise CYA that far.

    My advice: fix the pH as mentioned above. Buy some CYA granules and add enough to raise CYA to 30ish and SLAM at 12 FC. Once the SLAM is complete, add the rest of the CYA to get you to 50. Odds are you'll be backwashing that DE filter a bunch, so the CYA value will go down a little from dilution before you're at that point. Be sure to use the sock method to add it, otherwise you might end up backwashing it all away before it dissolves!
    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: Pool out of whack, help needed

    Quote Originally Posted by Texas Splash View Post
    Hey Houston! I would leave CYA at 20 until after the SLAM to save you on some bleach. Raise it up after you pass all 3 criteria. As for the stubborn spots, just continue to brush a few times daily and follow everything else listed on the SLAM page (pump 24/7, clean filter, etc). Of course maintain that SLAM/shock FC of 10 based on a CYA of 20. Today's wind (at least in our area) was brutal today. It looks like someone cut their lawn and dumped it on our pool.

    No sweat, the SLAM will fix it. If you still think you have stains or yellowing after passing the 3 SLAM criteria, let us know. Oh, and as for the pH .... well, your SLAM FC shock is only 10, so if you let it come to about an FC of 9 real quick, you can test pH and adjust to the 7.2-7.5 range, then kick-up FC to 10 again.

    After the SLAM, yes, you can use the pucks if you want, just keep an eye on the CYA.
    Thanks for your reply, @TexasSplash! How do you tell if the filter needs a cleaning mid-SLAM?


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Texas Splash's Avatar
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    Re: Pool out of whack, help needed

    Keep watching your filter pressure. Once it increases about 20-25% over your clean/starting pressure, it's probably time to backwash.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
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    Re: Pool out of whack, help needed

    Quote Originally Posted by Richard320 View Post
    When FC is below 10 during one of your checks, test pH and fix it. Just add the acid and grab the brush and make a quick lap around the pool. Then resume the SLAM.

    You want to keep the CYA level down around 30 or so while SLAMming, if possible, because that keeps the target FC lower while still protecting the CYA from sunlight losses.

    You can use dichlor or trichlor to raise CYA while you chlorinate, but they are both acidic, so you'll be juggling three parameters at once if you try that. Effects of Adding Chemicals at the bottom of poolmath will show you what each chemical does. Note the pH change is an estimate, and the more you try to add, the farther from reality it becomes. Which is a longwinded way to say I wouldn't rely on pucks to raise CYA that far.

    My advice: fix the pH as mentioned above. Buy some CYA granules and add enough to raise CYA to 30ish and SLAM at 12 FC. Once the SLAM is complete, add the rest of the CYA to get you to 50. Odds are you'll be backwashing that DE filter a bunch, so the CYA value will go down a little from dilution before you're at that point. Be sure to use the sock method to add it, otherwise you might end up backwashing it all away before it dissolves!
    Thanks for the detailed tips, Richard! Wasn't aware that brushing is helpful for muriatic, I've usually just poured it near a return . Also good to know about using a sock for CYA, wouldn't have occured to me. How did you deduce that I would be back washing a lot?


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Re: Pool out of whack, help needed

    Quote Originally Posted by Texas Splash View Post
    Keep watching your filter pressure. Once it increases about 20-25% over your clean/starting pressure, it's probably time to backwash.
    Ah OK! I've tried to follow that rule for general back washing but my pressure never really goes up appreciably, so I usually backwash when the pool gets funky like right now. In fact, I was planning my annual hosedown of the grids this weekend before realizing I had to SLAM stat.


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Re: Pool out of whack, help needed

    Quote Originally Posted by gustafson View Post
    Thanks for the detailed tips, Richard! Wasn't aware that brushing is helpful for muriatic, I've usually just poured it near a return . Also good to know about using a sock for CYA, wouldn't have occured to me. How did you deduce that I would be back washing a lot?


    Sent from my iPhone using Tapatalk
    Brushing speeds up the mixing is all, so you don't have to wait before you resume dumping jugs of bleach. You still want to dump any liquid chemicals in front of a return.

    The backwashing deduction comes from reading hundreds of threads here over the years. If your pool is really sludgy, you could load that filter up in an hour, no problem. But as long as your maintaining shock level, each time you backwash the interval will get longer between backwashes.
    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: Pool out of whack, help needed

    Update: checked the pool Sunday morning and saw I was at 7ppm FC, so proceeded to adjust pH (40oz muriatic). Then I added 40oz CYA granules to a filter sock in front of to near skimmer to bring CYA up to 30.

    When I checked conditions Sunday night:
    FC - 2.5 (way down)
    CC - 0.5
    CYA - 20 (no change!)
    PH: 7.5

    I added 27oz muriatic to bring pH to 7.3. To bring FC to 12 ppm (assuming CYA would eventually go up), pool math recommended 2.95 gal of 10% liq CL. I added 3 gal to be on the safe side. But when I tested Sunday night:

    FC: 17 (which suggests a 21kgal pool, not 30kgal!)
    CC: 0.5
    PH: 7.5
    CYA: 20

    Monday morning, the pool tested thus:

    FC: 14
    CC: 0.5
    pH: 7.5
    CYA:

    So essentially, I overshocked the pool, and am so far unable to adjust pH lower than 7.5 and move CYA up from 20.

    Am planning to let the FC ride down today, and not worry about lowering pH for now or trying to bring CYA up until the SLAM is complete. I'm wondering if the CYA is getting trapped in the skimmer or filter and whether I should hang a sock in front of a pool return so it stays in the pool? Pointers welcome!


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Re: Pool out of whack, help needed

    Some things to consider .... give the stabilizer just a little more time to register on your tests. While it should begin to increase shortly after dissolving, perhaps water temp or something else is delaying the increase. But yes, plan on an FC of 12 as your SLAM. That should do fine as long as your CYA doesn't shoot-up higher than 30. Remember it's always best to check CYA during a sunny day with the sun at your back for best results. It's good you adjusted your pH while you had the time. No problem with the slightly high FC. It will sink down soon enough to where you want it. Biggest thing now is to try and keep the FC steady at your SLAM/shock level until you pass the 3 SLAM criteria. Perhaps check the CYA in a couple days just to make sure everything you added registered as you anticipated.

    Pool size off? ....... perhaps. I would keep good notes for now on all of your different test readings. Make note of the NOW, GOAL, & RESULT, so you can compare. Comparing different tests this way (not just FC) can help you pinpoint pool volume since some of the tests are just a bit more tricky to count and/or a little more precise to read which should give you good numbers to validate. Good luck, and have a great day.
    Pat (a.k.a. Texas Splash) ~ My Pool: Viking Fiberglass; 17,888 Gal; Waterway Supreme 2-sp/2-hp pump; Hayward Ctg filter; TF-100 w/ Speed Stir
    Vital Links: POOL SCHOOL, RECOMMENDED LEVELS, RECOMMENDED CHEMICALS, Poolmath Calculator, SLAM, Chlorine/CYA CHART.
    If you enjoyed your TFP experience, please consider donating to Support TFP!

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    Re: Pool out of whack, help needed

    Quote Originally Posted by Texas Splash View Post
    Some things to consider .... give the stabilizer just a little more time to register on your tests. While it should begin to increase shortly after dissolving, perhaps water temp or something else is delaying the increase. But yes, plan on an FC of 12 as your SLAM. That should do fine as long as your CYA doesn't shoot-up higher than 30. Remember it's always best to check CYA during a sunny day with the sun at your back for best results. It's good you adjusted your pH while you had the time. No problem with the slightly high FC. It will sink down soon enough to where you want it. Biggest thing now is to try and keep the FC steady at your SLAM/shock level until you pass the 3 SLAM criteria. Perhaps check the CYA in a couple days just to make sure everything you added registered as you anticipated.

    Pool size off? ....... perhaps. I would keep good notes for now on all of your different test readings. Make note of the NOW, GOAL, & RESULT, so you can compare. Comparing different tests this way (not just FC) can help you pinpoint pool volume since some of the tests are just a bit more tricky to count and/or a little more precise to read which should give you good numbers to validate. Good luck, and have a great day.
    Thanks for the guidance, very reassuring and greatly appreciated!


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Re: Pool out of whack, help needed

    granular CYA takes awhile to register on the test. Just put it in a sock in front of a return and give it a good sqeeze every few minutes. Eventually all of the granulated CYA will dissolve in the pool and after about a week it will show up on your CYA test
    15,000 gallon free form Viking fiberglass pool. Hayward Star-Clear Plus C12002 cartridge filter. Hayward Swim Pure Plus T-15 SWG. Testing with TF-100 Kit. 2 speed 1.5HP Supreme pump. Dolphin Nautilus robotic cleaner

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    Re: Pool out of whack, help needed

    What do you know, pool test tonight (Monday) gave me CYA of 30. FC was 9 (drifted down from 14 in the morning) and CC was 0, so dumped a gallon of 10% liq. Cl which brought FC up to 14 (indicating a 20kgal pool). Look forward to seeing where FC ends up tomorrow. Once this SLAM is done, I plan to spring clean the skimmers and behind the lamps and hose down those DE grids for good measure. Thanks for all the guidance, this proved relatively painless (hope I'm not speaking too soon )


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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    Re: Pool out of whack, help needed

    Quote Originally Posted by gustafson View Post
    What do you know, pool test tonight (Monday) gave me CYA of 30. FC was 9 (drifted down from 14 in the morning) and CC was 0, so dumped a gallon of 10% liq. Cl which brought FC up to 14 (indicating a 20kgal pool). Look forward to seeing where FC ends up tomorrow. Once this SLAM is done, I plan to spring clean the skimmers and behind the lamps and hose down those DE grids for good measure. Thanks for all the guidance, this proved relatively painless (hope I'm not speaking too


    Sent from my iPhone using Tapatalk
    I would do the cleaning of the lamps, etc. before your SLAM is done. It may hinder your progress if you don't. (Sometime people can't pass the OCLT because there is hidden algae.)
    26' X 52" Intex Ultra Frame. Intex Sand Filter
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    Re: Pool out of whack, help needed

    Quote Originally Posted by PAGirl View Post
    I would do the cleaning of the lamps, etc. before your SLAM is done. It may hinder your progress if you don't. (Sometime people can't pass the OCLT because there is hidden algae.)
    Thanks for that tip. Turns out I did meet SLAM criteria this morning, but plan to keep FC at shock levels while I do a deep cleaning, and will hose down the grids too to be ready for the season. Thank you everyone for the the advice, y'all made the recovery painless!


    25,000 gal, in-ground, plastered gunite, Pentair NSF 60 DE Filter

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