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Thread: How do I determine SLAM target?

  1. Back To Top    #1

    Join Date
    Mar 2013
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    Central Iowa
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    How do I determine SLAM target?

    Ok, this is our 2nd year and I don't believe we ever really got crystal clear water last year. We have only in the last two weeks opened our pool. We finally have the water level up and have had our pump/filter running for a week and a half now. I did an initial test of the water with the TF100 kit. Don't have those numbers right in front of me, but little to no chlorine, CYA (dot never disappeared) was low and PH was high (8.2).

    I put some stabilizer/conditioner in the water about a week ago. It is still disolving. I have been dumping chlorine in like crazy using a target of 10 for SLAM, but I don't know if that is the correct goal or not. I went back last night and looked at threads from last year and it looks like the target was 12. Can you tell me how that is determined? I was using 10 as my goal because of the CYA/Chlorine chart. Since my CYA was low I used the chlorine goal that was listed with the CYA that was in the pool. Is that wrong? Should I be using 12 because I am working on raising the CYA to 30? If so, have I wasted a whole weeks worth of chlorine? About 20 gallons!!!!!!

    The water has improved, but we did see some algae floating a couple days after starting. The water has been aqua blue color, but quickly goes back to a darker green. We have seen the bottom, but again only for short periods of time.

    I have been brushing the pool, as much of it that I can reach. I still can't get Wanda the Whale to work and don't know what to do with her. Her feet won't get moving. There is great suction, just no motion. I don't want to purchase a new cleaner and have the same issue in case it is something else and not Wanda. We have replaced the hose. I don't know what else to do.

    There does seem to be a layer of dust on the bottom of the pool, but there is not any leaves or debris.

    Would appreciate any help you have to offer. Frustrated at this point. Trying to read and re-read and I just can't get my pool to clean up. THANKS!!!!!
    2014 Used 33'x54" Wilbar Morada,deep end approx 28,800 gal.
    Hayward S180T1580S pump/filter combo,
    Pentair Aqualuminator light/return, Aquabot S2-50
    TF-100 kit, Initial fill with pond water
    South Central Iowa

  2. Back To Top    #2
    Texas Splash's Avatar
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    Jun 2014
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    Re: How do I determine SLAM target?

    To ensure you are doing the SLAM properly, there are a few things to get prepared:
    - Adjust PH to 7.2 - 7.5; don’t worry about it after that during the SLAM
    - Ideal CYA should be 30; the higher the CYA, the more bleach required
    - Have a good amount of “regular” liquid bleach on-hand to keep your FC high at all times

    After that, "maintaining" your FC level for a SLAM. IF your CYA was at 30, then a SLAM FC level would be "12". If your CYA was only 20, then it would be "10". Those numbers are obtained from the Chlorine/CYA chart link below in my signature. You should refer to that chart all-year round.

    So please post some TF-100 numbers and we can help validate what you need to do.
    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!

  3. Back To Top    #3
    Mod Squad JVTrain's Avatar
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    Re: How do I determine SLAM target?

    If you tested and your CYA was <20 then if you were to SLAM without adding any CYA, your target would be 10 FC. If you added CYA, still dissolving, what CYA level did you target? Whatever level you targeted, THAT'S the level you now use for your SLAM FC level. If you targeted 30, assume your CYA is now 30 and use 12 FC as your target. If you targeted 40, then it would be higher. See the CYA/Chlorine chart in my signature. The most important part of a SLAM is MAINTAINING that shock FC level as much as possible. Test multiple times every day and add bleach to get back to the FC or 1 or 2 FC over target is fine. The more often you test and dose, the faster it will clear. You can test as often as every hour when your schedule allows. Verify your actual CYA by testing for it again, several days after it has all dissolved. No need to test it until then.
    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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    Texas Splash's Avatar
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    Re: How do I determine SLAM target?

    Also, if you put stabilizer in there last week, it should be dissolved by now. If you are using the sock method in front of a return, simply squeeze it from time to time to encourage dispersion.
    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!

  5. Back To Top    #5

    Join Date
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    Location
    Central Iowa
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    Re: How do I determine SLAM target?

    So, if I have already been in the SLAM mode for several days and didn't correct my PH before I started, do I still need to do that? And can I get an accurate test result at this stage?

    I chose the target of 10 because the CYA was 20 or less. I did put stabilizer in and targeted 30. So I should actually be aiming for a SLAM of 12 not 10, correct?

    Also, when I do Pool Math during SLAM, do I have to enter test results in to all of the categories or can I just enter what the current chlorine level is and adjust from the? Do the other categories affect the amount of chlorine that I need to be adding? Does that make sense?

    I have been checking the pool at least times a day and the first day was about every two hours. It just seems like it should be making bigger changes more quickly. But, if I was targeting 10 and not 12 like I should have been, then maybe I have wasted a week of SLAM. Darn it.

    Any suggestions for Wanda? How do I get the "dust" type stuff off the bottom if I can't reach it with the brush and Wanda won't work.

    Do I need to do a full set of test results every couple of hours or only test for chlorine? I have only been testing for chlorine and putting that number in the FC on Pool Math and not entering any other test result numbers. Maybe I have this all screwed up.

    Of course, it doesn't help that we got 5" plus of rain the other night. I am sure that has the numbers thrown off also. We had to drain quite a bit off of the pool.

    THANKS so much!!!
    2014 Used 33'x54" Wilbar Morada,deep end approx 28,800 gal.
    Hayward S180T1580S pump/filter combo,
    Pentair Aqualuminator light/return, Aquabot S2-50
    TF-100 kit, Initial fill with pond water
    South Central Iowa

  6. Back To Top    #6
    Mod Squad pooldv's Avatar
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    Re: How do I determine SLAM target?

    PH test is not valid when FC is above 10. If it is below 10 test PH and adjust to 7.2. You only need to test FC and CC during SLAM and poolmath will give you the correct amount to add for FC. It will not give you the correct info for PH without the other numbers.

    More on using Poolmath here: Pool School - PoolMath

    Go ahead and switch to 12. You have not wasted a week, all the chlorine is still killing stuff, just not quite as fast.
    TFP Moderator
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