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Thread: Slow SLAM progress?

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    Slow SLAM progress?

    Just a few days ago I noticed a thin layer of green on the bottom of the pool, and commenced a SLAM. This is my first SLAM attempt since joining the site, so I want to make sure I'm on the right track:

    FC= 17 ppm
    CC= 0 ppm
    pH= 7.6
    CYA= 40 ppm
    Alkalinity= 80 ppm

    I started the SLAM two days ago, yet each morning since, when brushing the bottom and sides of the pool, I still see the same thin green layer. The deep end is still pretty cloudy; if there has been any improvement at all, I would say it's minimal. Why are my CC's 0? I thought that CC was an indication that you are actively killing off algae, yet both days since I started the SLAM, it has been 0. Am I being impatient, and this process takes several days? I guess I just thought that with 17 ppm of FC, the effects would be seen rather quickly.

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    Mod Squad woodyp's Avatar
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    Re: Slow SLAM progress?

    CC may or may NOT be present killin' algae. Your "thin" layer just might be a bit thicker than you thought! Hang in there till you meet all 3 criteria.
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    Re: Slow SLAM progress?

    On second measurement, the pH may actually be in the 7.8-7.9 range. I've read that high pH can render chlorine not as effective. At what high levels of pH should I start to be concerned that the chlorine isn't performing its job? I'm guessing it has gone up due to the 4 gallons of liquid chlorine I have put in over the past two days. Should I add a little pH down?

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    Texas Splash's Avatar
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    Re: Slow SLAM progress?

    As woody stated ... hang in there and be patient. SLAMs can take several days to a week or two. But since I don't see above what test kit you used, I was just curious if you had the TF-100 or Taylor K-2006? Also, if you are new to testing, are you confident that your CYA s 40? If so, then your FC of 17 is great as long as it never drops below that all day/night. But imagine for a moment if your CYA was actually 50. Then your SLAM FC would actually be 20. So even though it's only been two days, I still like to remind people how important accurate CYA is to ensure they are really killing the algae. Also, don't forget you can scoop-out as much muck as possible to help take some relief off of the bleach. Be patient, and good luck!

    - - - Updated - - -

    Don't worry about PH during a SLAM. The high FC messes-up the PH reading.
    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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    Mod Squad YippeeSkippy's Avatar
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    Re: Slow SLAM progress?

    Also, what type of filter do you have and are you cleaning it up as appropriate? Filters often need backwashing or cartridge cleaning during a SLAM as they get full of algae
    My Amazon Smile for November12K Fiberglass IG, Infinity 4000 automatic cover, SWCG, Hayward Sand Filter, Hayward 1.5 Pump, Doheny Discovery Robot, Savi Melody LED pool lights, outdoor speakers and other assorted doo-dads. Sundance Altamar Hot Tub.
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    Re: Slow SLAM progress?

    I am using the TF-100 test kit. I have a brand new 1 hp Hayward Max Flo pump with matching Hayward 21" sand filter. Even during my slam, the pressure in the filter has not moved from 15 psi. In fact, since installing the new equipment in May, I have only had to backwash maybe 2-3 times due to the psi rising above 20. I make sure to rinse after each backwash to prevent channeling.

    I am fairly confident that the CYA is 40. It was 20 last week, and I added the appropriate amount to target 40 ppm. I will measure it again to make sure. Are you saying that if the CYA was actually 50, the 17 ppm would be useless at that CYA level? Is it really that fine of a line between success and failure?

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    Texas Splash's Avatar
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    Re: Slow SLAM progress?

    TF-100 Yes - exactly. The 10 ppm difference of 40-50 CYA makes a big difference with the FC. It's just one of those items that would be good to be absolutely sure of to ensure you're getting the best results out of your SLAM.
    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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  8. Back To Top    #8

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    Re: Slow SLAM progress?

    The FC level is a percentage of your CYA level for both regular maintenance as well as for a SLAM. The difference is important.
    5900 G Fiberglass IG pool (circa 1990), SWG Hayward Aqua Rite GoldLine (2013), IntelliFlo Variable Speed Pump (2013), Hayward Pro Sand Filter (circa 1990), Well water (no iron or other metals fortunately), test with Taylor K2006C, Charleston, SC

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