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Thread: Is this 'dirt' algae?

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    Question Is this 'dirt' algae?

    Hello all, we've recently set up our pool again after moving. I keep finding this black 'dirt' looking stuff at the bottom of our pool even after daily vacuuming. Do you all think this is algae? I've been using an algecide that kills all algae for the past 4 days and still I wake up to more of the 'dirt' on the bottom of the pool.

    Attachment 50093
    Attachment 50096
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Re: Is this 'dirt' algae?

    Do you have a test kit? What are the results?

    It could be algae, it could be dirt/pollen/whatever from trees.
    18k gal 32'x16' IG vinyl, sand filter, TF 100 test kit
    Newbie pool owner since April 2016

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    Mod Squad JVTrain's Avatar
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    Re: Is this 'dirt' algae?

    Algaecide does not kill algae. It can prevent algae if chlorine levels drop too low based on the current CYA level but algaecide does nothing to eliminate algae.

    Can you post test results?
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: Is this 'dirt' algae?

    I do have a test kit.
    My CYA is about 30
    CL is high at about 7.6 (I think, it's dark yellow matching the top colors on an HTH reader)
    PH is about 7.5
    I'm not sure about the others. I'll have to test again.
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Mod Squad pooldv's Avatar
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    Re: Is this 'dirt' algae?

    If you have an FAS/DPD chlorine test then do an Overnight Chlorine Loss Test to tell for sure if there is algae in the pool or it is dirt or debris. If you don't have one you can order it from TFTestkits.net.
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    Re: Is this 'dirt' algae?

    I am out of my FAS/DPD solution. I will order some, but I don't think I'm losing any chlorine because the chlorine level has been very consistent between 5 and 11 (the top mark). I have been keeping it that high to shock the pool when I started seeing the 'black stuff' or dirt/algae. When it got really dark yellow, I lowered the salt timer to 4 hours instead of 6. It is coming down slowly, but even before the SWG comes on the chlorine level is stable at the same window mark.

    Is it possible to have algae when the CL is so high? Also, my neighbor has TONS of pine trees, bushes, and some other large tree could it be coming from the trees even though they are not over my yard at all?

    One other point is that it vacuums up really easily. Would algae do that? I think it's algae because of how it gathers together in cloud like clumps in the middle of the pool and lines all of the seams.

    Thanks
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Mod Squad JVTrain's Avatar
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    Re: Is this 'dirt' algae?

    A FAS-DPD test is required to perform the overnight chlorine loss test. It's the definitive way to tell whether or not something is growing in your pool. Should have a FC loss overnight (sundown to sun up) of 1 ppm or less. It's possible for algae to get started any time your FC drops below the minimum amount for your CYA. It can also happen if the FC drops too low locally in one area of the pool due to poor circulation or lack of regular brushing. Then algae can survive even at FC levels above the maintenance minimum until they are aggressively attacked using the SLAM procedure and brushing to remove them from their location and kill the algae.
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: Is this 'dirt' algae?

    Okay. My HTH test kit does have a way to test FC, it says to leave the water in the tube for 5 minutes and check the level of change. I know this is not as accurate as the FAS/DPD check, but until I'm able to purchase it, I'll do that test.

    One more question. Yesterday I noticed that my water is very cloudy. Do you think that would have something to do with it and is there a BBB way to clear up the cloudiness?

    - - - Updated - - -

    Okay. My HTH test kit does have a way to test FC, it says to leave the water in the tube for 5 minutes and check the level of change. I know this is not as accurate as the FAS/DPD check, but until I'm able to purchase it, I'll do that test.

    One more question. Yesterday I noticed that my water is very cloudy. Do you think that would have something to do with it and is there a BBB way to clear up the cloudiness?
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Re: Is this 'dirt' algae?

    Quote Originally Posted by ummhasan View Post
    Okay. My HTH test kit does have a way to test FC, it says to leave the water in the tube for 5 minutes and check the level of change. I know this is not as accurate as the FAS/DPD check, but until I'm able to purchase it, I'll do that test.

    One more question. Yesterday I noticed that my water is very cloudy. Do you think that would have something to do with it and is there a BBB way to clear up the cloudiness?
    8 out of 10 times cloudy water is a sign of the beginning of an algae bloom, and the remedy is chlorine.

    You really need to get a proper FAS/DPD chlorine test kit ASAP. If you indeed have an algae bloom in progress you will need to SLAM the pool.

    It will be nearly impossible to do an OCLT or SLAM without the proper test kit.

    Dom
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    Re: Is this 'dirt' algae?

    Before I begin to SLAM after checking the FC, I need to make sure my CYA is accurate. I no longer have the little squeezy bottle to dispense the mixture into the CYA reading tube so I've been just filling water and the reagent 50/50 in the larger measuring tube used to check for alkalinity. Is there a set mixture amount that I need to mix? If my CYA is really at 30, then I first need to adjust that because I have a SWG. Also, I have stabilizer that I can add, but wouldn't it be better to just use shock to slam and bring up the cya at the same time?
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Re: Is this 'dirt' algae?

    You don't want to any stabilizer/CYA until you have determined whether you need to SLAM. You need a lower level of stabilizer if you have to SLAM. With your water turning cloudy, you really need to SLAM.

    Best to order the reagents and testing supplies/tubes you need. In the mean time, run the pump 24/7, brush daily. Update your signature to show how many gallons are in your pool and we can give you a guesstimate on how much chlorine to add while waiting for your testing supplies.

    Refresh by reading up on SLAMing.
    Karen
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    Re: Is this 'dirt' algae?

    Thanks. I did reread the SLAMing section and have updated my signature. Is brushing really necessary with a vinyl intex pool? The bottom feels pretty clean. I've actually never brushed it while it was up for 2 years at our old house and had crystal clear water.
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Re: Is this 'dirt' algae?

    Brushing is essential because algae forms a biofilm that protects it from FC. Brushing removes the biofilm so that the FC and kill the algae. Brush daily while SLAMing and brush weekly when in maintenance mode.

    I wouldn't add more than 1/2 jug of 8.25% bleach a day until your reagents arrive.
    Karen
    33K IG w spa plaster, Pentair 1HP Whisperflo, DE Filter, SWG CircuPool RJ-60, Dolphin Triton Plus, Raypak Dig 336K BTU, TF-100.
    Pool Math Chlorine / CYA Chart SLAM - Shock Level And Maintain
    2017 replaster/retile

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    Re: Is this 'dirt' algae?

    Okay, I've received my regents and tested, but I've been adding 1/2 gallon bleach for the past 5 days..
    Last night via a FAS DPD test:

    FC 6 (12 drops)
    CC .5 (1 drop)

    This early afternoon (forgot in the early am and after SWG turned on for about an hour) via FAS-DPD:
    FC 5 (10 drops)
    CC .5 (1 drop)

    The water is much clearer after all the bleach slamming.
    CYA is currently at about 35

    Here is a photo of my OTO and PH test:
    Attachment 50612
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Re: Is this 'dirt' algae?

    Can you post the full test results like this:

    FC
    CC
    pH
    TA
    CH
    CYA

    Thank you.
    32K gallon Plaster - 1hp Hayward 2 speed Super Pump - Hayward S200 Sand Filter - TF100XL
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    Re: Is this 'dirt' algae?

    FC 6
    CC .5
    pH 7.8
    TA ?
    CH ?
    CYA 35
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Re: Is this 'dirt' algae?

    I would lower your pH to 7.2 tonight.

    Then perform the OCLT: Pool School - Perform the Overnight FC Loss Test (OCLT)
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
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    Re: Is this 'dirt' algae?

    The pool calculator has always been a bit confusing for me. There are two boxed, each seems to be: 1. Goal or 2. Not Set up.

    I'm not really sure what to put where to see how much baking soda to put in to lower the ph.
    18X48 Intex Metal Frame - about 6000 gallons, Intex 2,650-Gallon Sand Filter Pump, Intex Krystal Clear Saltwater Filtration System, BBB care method

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    Mod Squad JVTrain's Avatar
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    Re: Is this 'dirt' algae?

    Are you using the Pool Math link at the top of the page? http://www.troublefreepool.com/calc.html

    Here is a tutorial: Pool School - PoolMath
    Joel - TFP Moderator - Minnesota - **Become a TFP Supporter!** Helpful Links: ABCs of Pool Water Chemistry - SLAM Procedure - Chlorine/CYA Chart
    40x20 Pool: 32K Gallons * Vinyl * Bleach Chlorination * Hayward S270T Sand Filter * Pentair SuperFlo 1 HP * Teledyne/Laars Heater * AquaVac Tigershark * TF-100 w/ SpeedStir
    Isolated Spa - 345 Gallons

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    Re: Is this 'dirt' algae?

    Baking soda does not lower ph. You need to put in your ta in pool math before you can adjust your ph. Pool math will tell you what to add and how much. Ph goal is 7.2.

    Karen
    33K IG w spa plaster, Pentair 1HP Whisperflo, DE Filter, SWG CircuPool RJ-60, Dolphin Triton Plus, Raypak Dig 336K BTU, TF-100.
    Pool Math Chlorine / CYA Chart SLAM - Shock Level And Maintain
    2017 replaster/retile

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