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Thread: Help...Green slime wont go away

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    Help...Green slime wont go away

    I'm a beginner with the bbb method and I'm loving it...but...I accidently abandoned my pool for 3 days and now I have green slime in the center of the pool resting on the bottom. I did put in one bag of Shock blue plus and bleach. I'm replacing the filter cartridge everyday...yesterday the filter look greyish in color but today it is more of a rust color. I know I need a better water tester but currently I have AquaChem 6way test strips. My readings are...
    TOTAL HARDNESS...175
    TOTAL CHLORINE...9
    FREE CHLORINE...10
    BROMINE...20
    PH...6.8
    TOTAL ALK...90ISH
    STABILIZER...120ISH

    Please help...my kiddos are so ready to swim.

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    Re: Help...Green slime wont go away

    Assuming your test results are accurate, your pool is overstabilized and has rendered the chlorine ineffective enough to let algae grow.

    The only solution to that is to drain and refill about 60% of your pool and get the stabilizer (CYA) down to around 50ppm.

    Then you can shock the pool and get it cleared up and sanitary for swimming.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Ohm_Boy's Avatar
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    Re: Help...Green slime wont go away

    Well, you are right in one thing - you certainly need a better tester. Here's why we don't trust strips...

    1) Your chlorine readings cannot exist in the real world, as it is not possible for free chlorine (FC) to be higher than total chlorine (TC).
    2) If any of the readings are even close, then your pH is [possibly dangerously] low (6.8 is generally the min of a tester's capability), and
    3) your stabilizer (CYA) is way too high.

    I really want to help, but I cannot, in good faith, make any real recommendations based on those readings, as I cannot really trust any of them. My guesses would be no better than drawing a 'fix' out of a hat.
    Without even a small test kit, (strips are seriously less than useless), could you take a sample to a pool store to test your water and post those results?
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    Re: Help...Green slime wont go away

    Bummer...! I appreciate your help....I was hoping for a quick fix. I do uave a question though...what makes my stabalizer so high?

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    Re: Help...Green slime wont go away

    what makes my stabalizer so high?
    It can be other things but, by far, the most common thing is the use of "pucks". They keep adding stabilizer and it accumulates to the point of making the chlorine ineffective.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Help...Green slime wont go away

    Quote Originally Posted by hhurley81
    Bummer...! I appreciate your help....I was hoping for a quick fix. I do uave a question though...what makes my stabalizer so high?
    "...I did put in one bag of Shock blue..."

    The MSDS shows it as Sodium dichloro-s-triazinetrione 2893-78-9 63% That's Dichlor. pool-school/swimming_pool_definitions_abbreviations Each time you add chlorine, you also add stabilizer; the chlorine breaks down and disappears, the CYA does not. It just keeps building and building and building....
    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: Help...Green slime wont go away

    Ok..thanks so much! I just went and quickly retested since the last one I did was last night.
    TOtal hardness. 175
    Total chlorine. 10
    Free chl 10 bromine 20
    Ph 6.8
    Total alk 40
    Stabilizer 75

    I will definately be getting a nee tester but for now wth new numbers do I still meed partial drain?

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    Richard320's Avatar
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    Re: Help...Green slime wont go away

    Quote Originally Posted by hhurley81
    Ok..thanks so much! I just went and quickly retested since the last one I did was last night.
    TOtal hardness. 175
    Total chlorine. 10
    Free chl 10 bromine 20
    Ph 6.8
    Total alk 40
    Stabilizer 75

    I will definately be getting a nee tester but for now wth new numbers do I still meed partial drain?
    This is why we discourage test strips. 120, 75, why not call it 200, or 50? There's no way of knowing if or how much you need to drain unless you have an accurate test result. Even the best CYA test is only good to about +/- 10 ppm.
    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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    Ohm_Boy's Avatar
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    Re: Help...Green slime wont go away

    .I was hoping for a quick fix.
    I know, and I'm sorry. Here's the best I can give you right now...

    1) Your pH is low. It needs to be between 7.2 and 7.8. Lower numbers are more acidic. While 6.8 is low, it is also the lowest level that most tests can report, so even if it were 5.0, it would show up on the test as 6.8.
    You can raise this by adding 20 Mule Team Borax (or if you just want to spend a lot of money, a commercial 'PH-UP' product), but I cannot tell you how much to add because I don't know how low it is, and I don't know how big your pool is.

    2) Stabilizer, or CYA, is good to keep sunlight from depleting your chlorine, but it also reduces the effectiveness of the chlorine. Once it gets over around 60-80, it becomes extremely difficult to keep enough chlorine in the pool to keep it sanitary. Most chlorine tablets, or pucks, are Trichlor, which add 6ppm CYA for every 10ppm chlorine. Powder (Dichlor) adds 9ppm CYA for every 10pmm chlorine. Chlorine gets used up, but CYA is cumulative, and it does not go away except by water replacement. Here again, 120 is about as high as a strip can measure (100 is the max for most "disappearing dot" tests) so when your results show 120, they could actually be much, much higher. The fix is to drain off and replace some of your water, but I cannot really say how much. Maybe 50% would be a good starting target.

    3) Chlorine levels should be determined by stabilizer. See the CYA/Chlorine chart link in my signature for more info. To fix your 'green', you'd need to get your FC up to shock level and hold it there until everything is dead.

    In order of what to do, you should replace enough water to get your CYA down to 50 or so, then adjust the pH to 7.2-7.8, and then add enough liquid chlorine to reach shock level, and check/replenish it until the level holds. See "Overnight Chlorine Loss Test" in Pool School (link in my signature).

    But all of this hinges on the results of your test strips, which can just be crazy wrong. Do you have a pool store nearby?
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    Ohm_Boy's Avatar
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    Re: Help...Green slime wont go away

    Quote Originally Posted by hhurley81
    Ok..thanks so much! I just went and quickly retested since the last one I did was last night.
    TOtal hardness. 175
    Total chlorine. 10
    Free chl 10 bromine 20
    Ph 6.8
    Total alk 40
    Stabilizer 75

    I will definately be getting a nee tester but for now wth new numbers do I still meed partial drain?
    I.. I.. maybe? Which test should we believe?
    Seriously, as much as I know how error-prone pool store testing can be, I'd take it in a skinny minute over the strip results. If you can't find a pool store to test your water and give you the results, can you find even a little 5 or 6-way test kit at WalMart or Home Depot? Just please, no strips.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    Re: Help...Green slime wont go away

    There is a pool store about an hour away but they don't reopen until Tuesday. I have a kit from last year not sure if its any better or worse. Aquachem 3 way test kit. Bromine, chlorine and ph. Its drops that u put into water.

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    Ohm_Boy's Avatar
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    Re: Help...Green slime wont go away

    Try the kit, and let us know what you get. Also, how big is your pool?
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  13. Back To Top    #13

    Re: Help...Green slime wont go away

    Ok..just tested with aquacuem 3way drops kit. Sorry..the pool is an intex 5300 gallon (15 ft x 4 ft).
    PH 7.6
    BROMINE (chart only goes to 11.0 which should be very yellow but it bypassed yellow and is Crayola orange).
    FC and CC only goes to 5.0 which should be bright yellow at highest reading but it bypassed it also at Crayola orange too. Still thinking a partial drain is best?

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    Ohm_Boy's Avatar
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    Re: Help...Green slime wont go away

    The pH of 7.6 is a much better reading. We'll all hope that this is a more correct reading and press on. Fingers crossed.

    The Bromine/Chlorine thing can be confusing, since one test is used for both, so ignore Bromine and just focus on Chlorine. Your tester only goes to 5, and it appears that your FC level is higher than that. Maybe close to 10 as reported by the strips. Maybe not. But higher than 5. How high it needs to be is determined by the CYA (stabilizer) level, so let's' move on...

    What do we use for a CYA level? 120? 75? Tough call. I'm going to suggest you go ahead and do a 50% drain/fill which we can hope will take the level to somewhere in the 30-60 range, which would be about perfect.

    So, yeah. Do a drain/refill of about half the water.

    PH: Once the pool is full, re-check the pH. We want it between 7.2 and 7.8, prefer it to be 7.2-7.4 for now.

    Shocking: Then add 2 gallons* of laundry bleach. Regular, unscented, bleach. This will hopefully get your FC level to somewhere around 20-24. You'll want to brush the pool occasionally/daily - walls and floor - while you're shocking. Do NOT use powder or tablets. Trust me.

    *Bleach note: Check the label for Sodium Hypochlorite strength. It should be 5.25% or 6%. If you have liquid chlorine from a pool store (often sold as liquid shock), it'll be 10-12%, and you'd add one gallon. If it's unmarked or less than 5.25%, don't buy it.

    As the FC level drops to 18 or 16, add 2-3 cups of bleach to kick it back up.

    You're gonna have trouble measuring the amount of chlorine that you'll need for this, but if you mix your water sample 50/50 with distilled** water, and your strips measure 10, then you may be close. (**Be sure to use distilled water, as it will not have chlorine in it, and won't taint the test results. Tap water contains chlorine.)

    This will start killing the green goop. The chlorine should go away fairly quickly as it is used up killing the algae, so check it periodically and add more. You should probably think about a run to Wal-Mart, or Sam's club, or Aldi's. You're gonna need bleach.

    Keep the filter running. Clean it or replace it as needed.

    This is kind of an emergency procedure, 'cause I'm really guessing since I really don't know for sure anything about your levels. I'm largely driving blind until I can get real info.

    Inadequate testing will ultimately cause you a lot of grief, and cost you time and money. I'm gonna strongly suggest that you get yourself a real tester, such as the TF-100 from our own Duraleigh at tftestkits.net, or the K-2006 Taylor kit.

    And when you have a few minutes, read up on Shocking your pool

    Also, you should know that the pool problem isn't really just from 3 days of being ignored, it's from the CYA buildup which stems from using stabilized chlorine products, like the shock powder and pucks, which eventually makes the chlorine ineffective. Well, that and 3 days of being ignored. Smile. I'm just picking on you. Hang in there, and we'll get you through this.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

  15. Back To Top    #15

    Re: Help...Green slime wont go away

    Thank u so much...I really appreciate all the great info. Off to start a partial drain...I started the year off with 1" chlorine tablets to finish up all the product. I knew I shouldn't have

  16. Back To Top    #16

    Re: Help...Green slime wont go away

    Ok yall...I started draining my pool and when it reached the half way mark I noticed that the stuff in the bottom of my pool was still there except it now looks like a rusty color and none of it was draining. So I decided to go ahead and do a complete drain and scrub it really well. Now it is cleaned and completely perfect...lol...but local pool store is closed so I haven't picked up accurate test yet. With a 5300 gallon pool I'm not sure what I meed to start adding. Fc, bromine and CC are 0 but PH is 7.2. Any recommendations?

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