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Thread: First time SLAM - FC levels WAY high after first bleach add?

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    First time SLAM - FC levels WAY high after first bleach add?

    So we finally got our pool setup and are "SLAMing" for the first time. I have a TF-100 test kit and the first test of the FC level was 1.5. I just dumped enough Bleach into the pool to get the FC level up to 14 since our CYA was 35 (pool calculator said 3.5 of my 6% 96-oz jugs). According to the SLAM method, I am supposed to test the FC level every hour for a while and keep adding bleach each hour to maintain the FC level. I just tested the FC for the first time 1 hour after adding 3.5 bottles of bleach, and its 40! I'm assuming this is because the water hasnt had time to mix around? But I'm wondering why it says to test it every hour, b/c obviously thats not enough time to mix if the pool turns over every 8 hrs (thats about what I calculated with the pump I have). Any ideas? It takes a ton of the chlorine test liquid stuff to find out that the level is 40 (have to keep adding drops forever), so i dont want to waste it and run out before I even finish the SLAM process...
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Beens's Avatar
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    Re: First time SLAM - FC levels WAY high after first bleach

    Just going to jump in here for a quick response and I'm sure someone more qualified than me will answer very soon...

    They're going to want a full set of your test numbers and the info about your pool would be very helpful such as, size, how many gallons, what kind of pump/filter.

    Also, you said you just got the pool setup...I'm just curious about how the water looks (clear? cloudy? green?)...I bet the experts will ask that too.

    There's a quickie answer to get you prepared for giving more info...

    Experts to follow!!
    18' x 48" (42" water depth) Intex Metal Frame 6,700 Gallons
    Hayward Power-Flo LX 1.0 HP pump
    Hayward Pro Series S166T Sand Filter
    Original Intex Floating Skimmer

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    Charlie_R's Avatar
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    Re: First time SLAM - FC levels WAY high after first bleach

    You can use the 10 ml mark on your sample tube so each drop of R-0871 counts as .5 (watch that typo in the instructions! misprint of .05).

    I am in the habit of counting the drops as half; one; half; two; half; three.... you get the idea.

    With the 25 ml sample each drop is .2, and for our purposes we don't normally need that high of accuracy.

    Are you sure you input your gallons correctly in the pool calculator? That has gotten many people as well, including me......
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Re: First time SLAM - FC levels WAY high after first bleach

    13k gallons, vinyl AGP (oval)
    1.5 HP pump, 150 pound sand filter
    PH 7.2
    TA 90
    CYA 35
    Starting FC 1.5

    The pool water is green. Long story but we had various issues so it took a while to be ready to start slamming. By that time some algae started to grow. In the last 7 days its gone from cloudy to slightly green, to pretty green where the bottom is pretty difficult to see.
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Re: First time SLAM - FC levels WAY high after first bleach

    Quote Originally Posted by Charlie_R

    Are you sure you input your gallons correctly in the pool calculator? That has gotten many people as well, including me......
    I had my gallons wrong at first too... My pool is 18'x48" so I had put that in. Then I realized that my water wasn't actually that deep, just the frame! Had to change it to 42" which brought down the amount of gallons. Wasn't a huge difference but I'm glad I caught it!
    18' x 48" (42" water depth) Intex Metal Frame 6,700 Gallons
    Hayward Power-Flo LX 1.0 HP pump
    Hayward Pro Series S166T Sand Filter
    Original Intex Floating Skimmer

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    Re: First time SLAM - FC levels WAY high after first bleach

    You can add your pool info to your signature line by using the User Control Panel, linked in the upper left of this page. Also in the UCP you can add your location, as it will often modify the advice given here to account for your location. You wouldn't want advice for Arizona when you live in Maine, right?
    15'x48" 4500 gallon Intex pool, buried 1.5 ft. Pac-Fab Dynamo 3/4 hp pump. Hayward S180T sand filter, bought used. Taylor K-2006 test kit. Rocket mass heater based wood fired pool heater.

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    Beens's Avatar
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    Re: First time SLAM - FC levels WAY high after first bleach

    I just put in your pool info and bleach info and it gave me the same results as far as what to add...

    Not sure why it would be so high. They usually say you only have to wait 30 minutes after adding to test. As long as there isn't something wrong with your pump it seems that it should have been mixed in fine by 1hr after you added it..

    Waiting to see what the experts say!

    I know when I just had an issue with my FC test I was asked if I was holding the drops vertically (upside down) and how much powder I used. I assume you are using the 10ml sample?
    18' x 48" (42" water depth) Intex Metal Frame 6,700 Gallons
    Hayward Power-Flo LX 1.0 HP pump
    Hayward Pro Series S166T Sand Filter
    Original Intex Floating Skimmer

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    Re: First time SLAM - FC levels WAY high after first bleach

    Had wife read the directions for FC test over the phone to see if it had that misprint of .05. She is the one SLAMing today. She realized she was filling to 25ml mark instead of 10ml, hah! Some other test (I think TA) was using 25ml mark, so she got mixed up. I'll post the real FC in a bit when she gets the real #.
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Re: First time SLAM - FC levels WAY high after first bleach

    oops!!

    Glad you figured that out quickly. Now you can save those precious drops!
    18' x 48" (42" water depth) Intex Metal Frame 6,700 Gallons
    Hayward Power-Flo LX 1.0 HP pump
    Hayward Pro Series S166T Sand Filter
    Original Intex Floating Skimmer

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    Re: First time SLAM - FC levels WAY high after first bleach

    Yeah she had to use 80 drops to find out it was "40"!
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Re: First time SLAM - FC levels WAY high after first bleach

    So the real FC # is 19.5. Still seems high to me, but not crazy high like 40, so we're getting closer. Questions about the gallons accuracy: You might be right, I might be over-doing it. The pool is 15x33. I found a site that said 16x32 with 52" wall is 13,200 so I was guessing mine was about the same or maybe a little less. But now I'm thinking its more like 10,900 to 11,500 since the water level really is only like 45 inches high.
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Beens's Avatar
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    Re: First time SLAM - FC levels WAY high after first bleach

    Yeah I was trying to remember what the box said about the depth of my pool but I've had it so long! I thought it said 42" but I wasn't sure except that I remembered it had the pool measurement and then an asterisk with another measurement in fine print!

    Then my husband said, why don't you just measure it?

    Well DUH.

    So I stuck a tape measure in and voila! 42" lol
    18' x 48" (42" water depth) Intex Metal Frame 6,700 Gallons
    Hayward Power-Flo LX 1.0 HP pump
    Hayward Pro Series S166T Sand Filter
    Original Intex Floating Skimmer

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    Re: First time SLAM - FC levels WAY high after first bleach

    Another quick note, where are you getting 6%. Most have been changed out to 8.25%. I have not seen 6% in a long time. That could also add to your overshoot.
    17500 gallon Doughboy AGP, Hayward DE filter, waiting for the 1.5hp DB pump to go out.
    Learn to take the advice here and be trouble free or use the pool store's advice. "You can't do both and get very far"

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    Re: First time SLAM - FC levels WAY high after first bleach

    ALDI . Cheapest liquid chlorine I could find per ounce of real chlorine in my area. They sell 3/4 gallon jugs of 6% for $1.29. Next best was Sams Club which would have been the 8.25% stuff, but more expensive per ounce of chlorine.
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Re: First time SLAM - FC levels WAY high after first bleach

    Oh ok.. Just have not seen it in awhile. Also I got 12000 for your pool.
    17500 gallon Doughboy AGP, Hayward DE filter, waiting for the 1.5hp DB pump to go out.
    Learn to take the advice here and be trouble free or use the pool store's advice. "You can't do both and get very far"

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    Re: First time SLAM - FC levels WAY high after first bleach

    yeah different calculators giving me different results. Also the pool is basically a 15' by 16' rectangle with 2 half circles on the ends. So i tried calculating it as a circle + rectangle combined as well and thats where one of those numbers above came from. So I'm determined it somewhere between 11-12k, just dont know exact. I'm going to act like its 11 for now and see what kinda numbers I get when I add the amount the pool calculator says.
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Re: First time SLAM - FC levels WAY high after first bleach

    So...just so you all see the progress. Pic 1 is how the pool looked before SLAM. Pic2 is the pool after a half day of slamming(real cloudy). Pic3 is the pool today, 1.5 days into the SLAM, the water is nearly crystal clear. I added DE to my sand filter last night and immediately saw a big improvement in the cloudiness. I've had to backwash 3 times with DE in the filter since last night (putting it in at each backwash). Might actually go for a swim tonight! I read on another post that its safe to swim during the SLAM as long as FC levels are no higher than shock for the CYA level in the pool.

    EDIT: Well dang, looks like the pic order is reversed, but you get the idea
    Attached Images Attached Images
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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    Re: First time SLAM - FC levels WAY high after first bleach

    I was sure hoping that was the case!

    Good Job there and congrats!
    TFP Moderator
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    28K Gal IG FreeForm, CLI Quartz, Pentair 36"SF & VS Pump, Dolphin M5, Rheem

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    techguy's Avatar
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    Re: First time SLAM - FC levels WAY high after first bleach

    Go swimming! I swim in most anything.

    Have you done an OCLT test? Looks like you might be close with that set of alien steps floating in air, above the liner of your pool.
    -- Guy --
    10K gallons in 21' Round 52 inch wall Aqualeader AG, Hayward Power Flow LX 1.5 HP pump motor, Hayward Perflex EC50AC DE filter w/Cellulose, Wide mouth skimmer, 2013 new Diver Dan (craigslist) to replace the faded old Hayward AquaBug. TF-100

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    Re: First time SLAM - FC levels WAY high after first bleach

    So....
    9pm last night - FC: 14
    6am this morn - FC: 14
    8:30am - (tested again because I forgot to test the CC level at 6am when I was a zombie) FC: 14, CC: very slightly pink(almost still clear) after adding 5 drops of the first stuff, and took one drop of the second stuff to make it clear. So CC level is .5 or less.
    And the pool is very clear. Filter still catching stuff, especially when I add DE to it, but water looks really clear. Only way I can tell anything is in the water at this point is holding a flashlight to the water at night.

    So, to me it looks like I meet the 3 criteria for ending the SLAM....After just 48 hours with the water being green this time 2 days ago. Thank you everyone! Now I have about 11 jugs of bleach left over - i was really expecting it to take more than the 5 jugs it took. Oh well, glad its done!
    15x33 AGP (somewhere around 11-12k gallons)
    1.5 HP Hayward PowerFlo Matrix Pump
    150 pound hayward sand filter

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