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Thread: Halfway? through my first SLAM

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    Halfway? through my first SLAM

    Hello
    Here are the results from my water test. I found all of the tests fairly easy to run except for the FAS-DPD test itself which was very difficult for me to get repeatable results. I watched the Taylor kit video and made sure I matched it. Here are my results and my comments:

    PH: 7.2 --> this is similar to the pool store results, they got 7.4 a few days and we have had rain since then.
    Alkalinity - 150 --> this is slightly higher than pool store results, but the pool store did show a slightly high alkalinity at the time, I ran the test twice and it is indeed roughly in this range.
    Calcium Hardness - 200
    CYA - 0 --> this is consistent with multiple pool store readings. And no, the water is not new, its from last year, no fresh water has been added
    FC - 1.5 --> this is consistent with the test strips, the free chlorine is low. The FAS-DPD did indeed change to pink after adding the powder so there definitely is some free chlorine, just not a lot.
    CC - 12 --> or some large value like this. It was hard for me to get consistent results with the FAS-DPD test. I believe the last time I did it was the closest to the correct method based on the taylor video and this also echoes the test strips: the test strips showed a high total chlorine, say around 10 but the free chlorine was not 0 but it must have been close to 0 based on strip color. With the Taylor, the water definitely turned deep pink after adding the R-003 5 drops, so there is definitely a decent amount of combined chlorine.

    So to be honest, the FAS-DPD seemed like a lot of work but it seems to be telling me roughly what the test strips did. I do agree that its much easier to gauge PH and alkalinity with the Taylor kit.

    So I assume I need to add some CYA and slam the pool? I want to be VERY careful with the CYA.

    The pool is 26700 gallons according to the Pool calculator (though this seems high, my deep end has sloped sides and I thought my pool installer listed it closer to 23000).

    Last year, we added too much CYA before we reduced combined chlorine to 0 and free chlorine to a decent value, and after the chlorine level was corrected the CYA went up to 100. I cycled in some new water and got it to 85 but it did not get back towards 50 until the end of the season. I have used liquid chlorine for the past few years, even a novice like me realized I did not like the powder, the liquid always seemed to worked better at establishing a chlorine level.

    I am guessing the CYA was eaten up during the off season based on what I have seen posted on this site.

    Please help with some recommendations.

    Thanks
    Scott
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

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    pwrstrk's Avatar
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    My first FAS-DPD efforts

    Welcome to TFP !
    With your CYA at zero and the high CC's your probably have ammonia problems.
    I would get the CYA level up to 20-30 ppm and SLAM the pool. If It's ammonia you will go thru a god bit of bleach to lower the CC's. Don't be surprised if you don't hold FC for long as the ammonia will eat the chlorine as soon as you pour it in. I would test and redose every 30 min's.
    How does your water look ? Any visible algae ?
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

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    Mod Squad jblizzle's Avatar
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    Re: My first FAS-DPD efforts

    I agree sounds like ammonia ... I would add 10-15ppm of FC and retest in 30 minutes ... and repeat until the FC seems to start to hold and the CC drops. You could add 20-30ppm of CYA to start dissolving while doing this. Then complete the SLAM process.

    If you test and add often ... you could likely get rid of the ammonia within a day.
    Jason, TFP Moderator
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  4. Back To Top    #4

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    Re: My first FAS-DPD efforts

    Thanks Jeff
    I am adding the CYA (instant conditioner) tonight and will slam the pool on Saturday.

    The water is clear, if one did not know about the water balance issues you would think it was swimmable. I have been skimming the top of the water daily. The pool was opened 5 days ago and vacuumed and the earth filter backwashed afterwards. This was before I knew about the chlorine issue of course.

    -- Scott

    - - - Updated - - -

    Thanks Jason for your help, will do.

    -- Scott
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

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    pwrstrk's Avatar
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    My first FAS-DPD efforts

    Sounds like a plan. I would get a dozen jugs of bleach to start. If you don't use all on the SLAM then you have some for everyday use. 😎
    Jeff
    24'x54" AG Morada RTR (by wilbar) 13'500 gal. Hayward Powerflo Matrix 1hp 2 speed. Hayward Perflex EC65 DE filter.

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    Mod Squad jblizzle's Avatar
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    Re: My first FAS-DPD efforts

    If you are using instant liquid CYA, I think I would wait until the ammonia was gone before adding it. The ammonia will convert the FC to CC way faster than the sun will destroy the FC.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
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  7. Back To Top    #7

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    Halfway? through my first SLAM

    Hello
    I started the SLAM process at 4PM yesterday (after sun left pool area). I had to SLAM due to low FC and high CC (around 12). Here is what I got:

    Time:
    ------

    4:40 FC = 1.5
    5:20 FC = 2
    6:00 low FC (only used test strips until I got a reading, was worried about amount of R871 I had left)
    6:45 low FC
    ..
    ..
    10:45 FC = 3.0 (results from this point confirmed with both the FAS-DPD and also a test strip)
    11:30 FC = 5.5
    12:30 FC = 5.5
    01:15AM FC = 6

    ... went to bed

    10AM FC = 0 but the good news is that CC is approx. 0.5 - 1.0

    .. so I got rid of most of the bad stuff

    I put in 23 gallons of 12% shock yesterday. (I put in 12 when opening the pool last week before I joined TFP, so that means 35 gallons so far).

    I have to buy a bunch more today now and the sun is out and will be in the pool area for 5 more hours

    The problem is that I added two bottles of instant CYA and the CYA is still low (its not 0 but its less than 30, hard to see results below 30 on my FAS-DPD test).

    Any advice other than to keep shocking? I will try and find a non-instant CYA product since the instant conditioner at Leslies has given me problems. I am guessing I should not
    have added it until today.

    Thanks
    Scott
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

  8. Back To Top    #8
    JasonLion's Avatar
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    Re: Halfway? through my first SLAM

    You are doing fine. Low CYA is way better than no CYA.

    Two bottles should have raised CYA by roughly 40 give or take. Did you give it an hour with the pump on before testing?
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

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    Re: Halfway? through my first SLAM

    Hello
    Thanks, yes I definitely waited before measuring CYA. One bottle was put in Friday and the other on Saturday, so now that its Sunday.
    This happened to me last year when shocking the pool, I put in the CYA (2 bottles) before the pool was truly shocked properly and it was registering low, so I added almost two more bottles and ended up with CYA=100
    So it really spiked on me. I am wondering the pool chemistry on that.

    So this year I played it safe and only put in 2 bottles and I really do not want to put in more until I get solid shock level FC ratings. There seems to be some relation there...
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

  10. Back To Top    #10
    JasonLion's Avatar
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    Re: Halfway? through my first SLAM

    Even though it usually mixes in quickly, the liquid CYA can be fairly syrupy/thick and doesn't always mix in right away, especially if the water is cold. Giving it a while longer before adding more is a good idea.

    In the mean time you should have enough CYA to finish SLAMing.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  11. Back To Top    #11

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    Second morning after start of SLAM

    Hello
    I am still losing chlorine, even though the CC was at 0.5

    Day 2 of the SLAM yielded these numbers at these times:

    2PM FC=0 Added 3 gallons 12.5%
    3:45 FC=4 Added 2 gallons
    4:30 FC=12
    5:30 FC=11
    6:15 FC=8 Added a half gallon
    7:24 FC=10
    8:30 FC=6 Added 1 gallon
    10:00 FC=9 Added half gallon
    11:00 FC=7.5 Added 1 gallon
    12:00AM FC=11
    1:20 FC=9.5
    6:20AM FC=3.0 CC=0.5 Added 2 gallons

    So I am still losing chlorine at approx. the rate of 1PPM per hour

    So I guess I will keep slamming, but an wondering now if it will ever end.
    And I have to worry about the sun later due to low CYA which did not rise to the level it was supposed to after adding
    2 gallons of instant conditioner on the weekend.
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

  12. Back To Top    #12
    ship of fools's Avatar
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    Re: Second morning after start of SLAM

    Your FC is dropping too low. If it is at 0, 4 or 3 as your numbers show you are not maintaining shock level even if your CYA is at 20 or 30. CYA levels sometimes take up to a week to show up so use what you expect it to be based on your addition of stabilizer.

    Keep on keeping on ... you will get there!
    21,000 gallon inground
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    Re: Second morning after start of SLAM

    Your FC is dropping too low
    Well, yes, but OP is checking and redosing almost every hour so it is not staying too low for very long.

    OP, don't worry about your CYA if your calculations are correct. It is in there even if the tests don't show as much as you added.
    So I guess I will keep slamming, but an wondering now if it will ever end.
    Actually, you can stop any time you want, but what will you do than?? These methods work on EVERY pool and your water is the same as everyone else's. Keep the faith and follow the SLAM article precisely. If you go slack, you will only cost yourself more chlorine or you will head back pool store hoping for the "magic cure" which they will gladly sell to you.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
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    3rd Day of SLAM - am I done or do I keep going? define "overnight"

    Hello
    Things are much better but it looks like I still did not pass the OCLT, here is what I got:

    Day 1- 23 gallons of 12% put in
    Day 2 - in the morning no chlorine level, but CC near 1, added 8 gallons throughout the day
    Day 3: (my CYA level is still low even though I added 2 gallons of instant which should have brought me near 30)

    6:20 AM FC=3 CC=0.5 - Added 2 gallons
    11:15AM FC=4 Added 2 gallons
    12:15 FC=12
    01:20 FC=10
    02:40 FC=10
    03:45 FC=6 Added 1 gallon
    04:45 FC=11
    05:45 FC=10
    06:45 FC=9 Added 1 gallon
    07:45 FC=12
    08:30 FC=12
    10:00 FC=11.5 CC=0
    11:15 FC=11.5
    12:15 FC=11
    ...
    05:30 FC=7.5 Added 1 gallon

    So from 6:45 PM to 5:30AM I lost about 5PPMs of FC, Day 3 used 6 gallons of 12%

    I am wondering how much time is "overnight". It was 11 hours after bringing it up to shock level for me (which is between 10-12 I guess. No CYA implies something like 10 while CYA is SUPPOSED to be near 30 which is more like 12. When I dose I put enough in to bring it to 12. 1 gallon should bring me around 12PPM now. I am going back to bed now and will not test again until late morning.

    I am almost out of R871 fluid, the test kit I bought really did not have enough to handle a SLAM this long, I have 2 larger bottles plus more CYA test plus more R870 on its way. The R871 should be here around Friday.

    So I am thinking I will do it one more day just to really ensure the pool is clean. I will have to use test strips and ensure they show the highest reading throughout most of the day and save the R871 for the end of day tests and tomorrow AM test.

    Thanks
    Scott
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

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    JasonLion's Avatar
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    Re: Halfway? through my first SLAM

    Several topics merged. Please keep everything relating to one problem/project together in one place.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  16. Back To Top    #16
    Mod Squad zea3's Avatar
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    Re: Halfway? through my first SLAM

    The overnight test must be conducted overnight to be valid. So if you have 10 FC at sundown, say around 8:00pm and test again at sunup, around 6:00am and have lost 5ppm during that time when the sun was off the pool you still continue the slam. When the sun is on the pool you will loose some FC to the UV rays. The overnight test eliminates the effect of UV rays.

    There are 3 criteria for ending a slam, clear water, CC of .5 or less, and you pass the OCLT.
    TFP Moderator
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  17. Back To Top    #17

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    Re: Halfway? through my first SLAM

    Okay,
    I have two of the three criteria, crystal clear water and CC=0 (verified last night and today with FAS-DPD). I guess I will keep going today checking every hour again.

    Thanks
    Scott
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

  18. Back To Top    #18

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    Re: Halfway? through my first SLAM

    Hello
    Day 4 results still have not passed the overnight test. Yesterday I kept the FC levels between 10 and 12 and it only dipped below in the morning and in the full heat of the day. I used 3 bottles of 12%, compared to 6 the prior day. (23 + 8 + 6 + 3 bottles of 12% so far).

    At 9PM last night I had: FC=12.5 CC=0.5
    at 6AM today I had: FC=10.0 CC=0.5

    So this is still more than 1 so I assume I continue. Does stuff dropping in pool have an affect on chlorine loss? We do indeed have spring here, we have big trees in our area and lots of stuff drop, I skimmed the pool multiple time yesterday.

    At 9PM last night my CYA was still very low, much lower than 30 is all I know since the FAS-DPD makes it hard to test anything below 30.

    I believe this morning has spent the R871 and I believe my delivery of the replacement does not arrive until mail delivery on Thursday.

    So I will have to use test strips and simply make sure the strips read a deep purple today and do a test tonight with FAS-DPD and hope I have enough R871.

    Thanks
    Scott
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

  19. Back To Top    #19

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    Re: Halfway? through my first SLAM

    By this time in your SLAM, I would suggest you reduce the testing interval to somewhere around 3 times daily. There is no need to test as often as you are in the latter stages of the SLAM
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

  20. Back To Top    #20

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    Re: Halfway? through my first SLAM

    After day 5 I measured this morning and had an FC=9 and a CC near 0. I did not measure until almost 10AM. I think I am fairly close. I could only do an official measurement this morning due to low R871 but I am supposed to get my replacement bottles today so I can resume official FAS-DPD testing for all my tests soon. I only needed to add 1.5 gallons of 12% yesterday to keep pool at shock level where I needed 3 the prior day.

    We have lots of stuff dropping in pool yesterday and we got about a quarter inch of rain last night which means some worms and such, seems like that stuff could affect results, do I still need to have a loss of only 1PPM when these things are occurring? Basically the first month after opening here always means a lot of extra pool cleaning work here and then it settles down to a fairly easy amount of maintenance (at least compared to the first month). BTW - its supposed to rain all day today too and tonight and tomorrow.
    -- Scott
    18 x 36 vinyl lined in-ground pool
    Hayward DE Filter
    Hayward Super Pump
    Hayward Propane Heater

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