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Thread: Need help with my SLAM

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    Need help with my SLAM

    Hi all - I need some help with the SLAM process. Iíve been going through dozens of gallons of 10% chlorine to maintain the pool at SLAM levels over the past week and although there has been marked improvement in the appearance of the pool, the chlorine continues to be consumed at a very brisk rate and doesnít show any sign of slowing down.

    Some background - My wife and I recently moved to upstate New York and bought a house with a pool (pool details in signature). Neither of us have ever owned a pool before. Before we moved in I read extensively about pools on this site. Thank you for all of the wonderful information!

    The pool we inherited didnít seem to be in very good condition. Although it was only mildly greenish (and very cloudy), brushing the side kicked up abundant half-dead algae and debris and the cartridge filter was caked with the same stuff. Ran some preliminary tests (using the TF100 test kit), cleaned the filter, and starting following the SLAM procedure. Over the next couple of days the greenish color disappeared and then the pool slowly started to clear. For the past couple of days it has been almost entirely clear and looks ready to swim in.

    The problem is that the FC is still dropping very quickly (both during the day and night) and Iím still using 8 to 10 gallons of 10% bleach every day just to keep it at SLAM chlorine levels. Itís losing 10-12 ppm just overnight (so it is nowhere near passing the OCLT) and this rate of chlorine consumption doesnít seem to be tapering at all. Iím beginning to worry that I may be overlooking something or doing something wrong. Itís also getting expensive and time-consuming. Iím including below all of my test results (which are mainly FC) and my actions in response to results. Iím also including a few pictures of the pool. I put a dark hose into the deep end (8 feet at the deepest) for the pictures just to demonstrate how clear the pool is. I also have a heater, but I havenít turned it on during the process.

    DATE TIME pH Chlorine (FAS) Action
    6/10 AM 6.8 1.5 ADDED 6 GALLONS 12.5%
    6/11 AM 1 ADDED 6 GALLONS 12.5%
    6/12 6:00 AM 7.2 13 ADDED 5 GALLONS 10%
    6/12 10:40 AM 24
    6/13 7:00 AM 7.2 5 ADDED 5 GALLONS 10%
    6/13 2:00 PM 20
    6/13 8:30 PM 12.5
    6/14 5:30 AM 7.2 2 ADDED 5 GALLONS 10% AND 5 BAGS SOLID SHOCK
    10:30 AM 30
    4:30 PM 16.5 ADDED 6 GALLONS 10%
    6:45 PM 32
    6/15 6:00 AM 16 ADDED 2 GALLONS 10%
    10:00 AM 21
    12:00 PM 19 ADDED 2 GALLONS 10%
    4:00 PM 21 ADDED 3 GALLONS 10%
    7:00 PM 28.5
    6/16 5:00 AM 14 ADDED 2 GALLONS 10%
    11:00:00 AM 17 ADDED 2 GALLONS 10%
    2:00 PM 18 ADDED 2 GALLONS 10%
    4:00 PM 23.5 ADDED 3 GALLONS 10%
    7:50 PM 25
    6/17 6:00 AM 15.5 ADDED 3 GALLONS 10%
    9:00 AM 21.5 ADDED 3 GALLONS 10%
    12:15 PM ADDED 1 GALLON 10%
    1:00 PM 25.5
    3:50:00 PM 18.5 ADDED 4 GALLONS 10%
    8:00 PM 25 ADDED 4 GALLONS 10%
    6/18 6:00 AM 25.5 ADDED 4 GALLONS 10%
    10:45 AM 30.5 ADDED 2 GALLONS 10%
    3:45 PM 23.5 ADDED 5 GALLONS 10%


    CYA ACTION
    6/10 <20 ADDED 120 OZ CYA
    6/12 40-45
    6/14 40-45
    6/18 40-45

    TA CH
    6/10 75 325
    6/11 70
    6/12 310 375


    Other notes - The pool has two skimmers, two main drains, and four returns. Three of the returns are in the shallow end, around the stairs. One return is at the deep end. They all have a forceful flow. Iíve been brushing the sides and floor as aggressively as I can and vacuumed a few times as well. Iíve used a small brush to try and get in the crevice behind the main drains and beneath the ladder. Iíve drained and cleaned out the filter itself with dilute bleach and replaced the filter cartridges. The skimmers seem to be working appropriately and Iíve been keeping them and the pump basket clear.


    A note on my alkalinity level - The pH of the pool was initially low (less than 6.8) and I made the embarrassing mistake of trying to adjust it with baking soda instead of soda ash or borax (I ended up adding a lot of baking soda). I did manage to get it up to 7.2 but, of course, now the alkalinity is high. Iím trying to follow the process of lowering the alkalinity by raising the pH (using a primitive waterfall-type feature- you can see it in one of the pictures).

    A note on CYA level - The TF100 kit includes a 50 ppm CYA standard, which is great practice for performing the test. Unfortunately, when I used to 50 ppm CYA standard, the black dot is not totally obscured when the test tube is filled to the 50 ppm mark. Itís mostly obscured, but not entirely. For me it becomes totally obscured around 35 ppm. My pool water is pretty similar - mostly obscured around 40-45 and totally obscured around 30-35. Not sure if this means that the standard is wrong, or Iím looking too closely. It would be nice to know although, either way, my CYA shouldnít be more than 40-45.

    Appreciate any help or suggestions you folks have.
    DSC05617-mod.jpgDSC05620-mod.jpgDSC05621-mod.jpgDSC05623-mod.jpg

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    tucsontico's Avatar
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    Re: Need help with my SLAM

    Well I'm not an expert but I expect one of our gurus to chime in soon. Firstly, your signature block has not shown up on your post so we're missing important data (pool size, etc.). From what I can gather you are winning the battle against algae. Remember, it didn't grow overnight and it won't go away overnight. I know it seems that 8 days of a SLAM should be enough, but each pool is different. Don't give up yet!

    However, you may have an issue with ammonia. If the pool sat with zero chlorine but with CYA in it a bacteria in the water can convert the CYA to ammonia. This will cause an EXTREME chlorine demand. I suggest you do a forum search for "ammonia." Hang in there!
    19,500 gal, 16' x 38' PebbleTec IG Pool, Built 4/2013; Pentair IntelliFlo VS 3050 3 HP Pump, Pentair Intellichlor IC40 SWG, Pentair IntellipH, Pentair 520 sq ft/150 GPM Cartridge Filter, A&A In-Floor Cleaner, Dolphin Nautilus Plus Robot (aka "Robbie"), Pentair EasyTouch Power Panel w/ Quick Touch 4 Remote Control, Autelis WiFi controller, Clear 12 mil Solar Cover on Presto SS Reel, Taylor K-2006 Test Kit.

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    Re: Need help with my SLAM

    Welcome to TFP

    You did study but you missed one important part you went nuke on it... while you would think that would work better it really just uses more chlorine... your free chlorine is holding so no ammonia

    Here is the CYA chart Pool School - Chlorine / CYA Chart CYA is sunscreen for chlorine, if you take your free chlorine over the CYA level it no longer gets protected and burns off...

    if your CYA is 30 your free chlorine would be 12
    if 40, you FC is 16

    What is happening is you're losing a bunch of your FC from the sun, you are still killing algae and whatever else is in there...

    You are very close to passing believe it or not... that water is getting there

    take your FC to 16, as many times as you can but don't go over, every 1 ppm over 16 the sun is killing the chlorine...

    try checking and adding FC as below or as many of those times you can
    6 am
    8
    10
    2pm
    5
    7
    9pm

    See if your sig is here Trouble Free Pool

    Let us know, I hope this helps
    Pool: Intex 16x32 15000 gal, 2 speed 340042, Pentair CC320 Filter, CircuPool SJ45 Salt System, Intermatic PE653RC; Hot Tub: 650 Gal SWG Megachlor
    links: pool school * Recommended-Levels * SLAM * CYA chart * Test kits * How To Post Pictures * Poolmath * OCLT ** Support your website if we helped you :) **

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    Re: Need help with my SLAM

    Sorry about the signature - guess it didn't save the first time. I think I've got it now.

    Thanks for the suggestion about the ammonia. I'll read up some more about it. Probably not an issue any more as my CC's have been 0.5-1 ppm over the past couple of days. But could have been slowing me down at the beginning. I'll grab an ammonia test from a pet store tomorrow and see if there is any left.

    Thanks for the support cowboycasey, I hope I am getting close to being done! I'm overshooting some of my FC targets, because the FC levels are dropping so fast and I don't want them to dip below shock level. Two nights ago the levels dropped 10 ppm overnight. Last night the level was stable, but only because I added 4 gallons of chlorine (10%) after my last measurement. So again, the pool ate 4 gallons of 10% chlorine at night. So something must be chewing up the chlorine other than the sun.
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Re: Need help with my SLAM

    Have you tested for CC?
    Is the pool being used?
    16' x 34' vinyl in ground - 16,500 gal.
    Hayward EC-75 DE filter with Hayward 1hp Super Pump
    TF-100XL Test Kit with SpeedStir

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    Re: Need help with my SLAM

    Quick update - Yesterday I only had to add about 6 gallons of 10% to maintain SLAM levels and that is a noticeable reduction compared to all the previous days (and it was bright and sunny - pool is in the sun all day). I thought the pool was already pretty clear, but it has actually gotten a little clearer over the past couple days. If it gets any clearer I won't be able to tell that there is any water in there - . Current FC this morning was 25. I'm going to let the sun take it down a little for me (since it really is a bit high for my CYA) and then overnight I'll really be able to see where I stand.

    - - - Updated - - -

    Also - mike1162 - CC's have been consistently between 0 and 1 except for the first couple days of the SLAM. Nobody is using the pool now. I've been keeping them out because of the high chlorine levels.
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Re: Need help with my SLAM

    Keep up the good work, you are almost there.. Great Job

    Its amazing how clear your water will be, just wait...
    Pool: Intex 16x32 15000 gal, 2 speed 340042, Pentair CC320 Filter, CircuPool SJ45 Salt System, Intermatic PE653RC; Hot Tub: 650 Gal SWG Megachlor
    links: pool school * Recommended-Levels * SLAM * CYA chart * Test kits * How To Post Pictures * Poolmath * OCLT ** Support your website if we helped you :) **

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    tucsontico's Avatar
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    Re: Need help with my SLAM

    Another thought regarding the high chlorine use could be the age of the chlorine. Is the 10% bleach fresh? Liquid chlorine loses potency very quickly. FOR HIGH QUALITY CHLORINE (lower quality chlorine will degrade faster) 12.5% chlorinating liquid at even 90F will have a half-life of around 70 days. At 75F, the half-life is around 220 days. Remember that these are half-lifes so the time it takes to lose half its potency and the loss will be faster early on as the concentration is higher. At 90F, the drop from 12.5% to 10.0% occurs in about 22 days -- again, for high-quality chlorine.

    May not be a factor but it is something to consider!

    19,500 gal, 16' x 38' PebbleTec IG Pool, Built 4/2013; Pentair IntelliFlo VS 3050 3 HP Pump, Pentair Intellichlor IC40 SWG, Pentair IntellipH, Pentair 520 sq ft/150 GPM Cartridge Filter, A&A In-Floor Cleaner, Dolphin Nautilus Plus Robot (aka "Robbie"), Pentair EasyTouch Power Panel w/ Quick Touch 4 Remote Control, Autelis WiFi controller, Clear 12 mil Solar Cover on Presto SS Reel, Taylor K-2006 Test Kit.

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    Re: Need help with my SLAM

    Update - I'm using up about 4 gallons a day of 10% chlorine now. So things seem to be headed in the right direction, although rather slowly. My impression from reading some other threads is that when I am done slamming and pass the OCLT, I should probably be consuming less than a gallon a day (barring unusual circumstances like a pool party or heavy rainstorm). I do kind of wonder where the algae that is consuming all of this chlorine is coming from. Could it be in the piping?

    tucsontico - thanks for the info on the chlorine half life. It's not staying with me long enough to really affect the strength (I'm running through it in less than a week) and it's really the ppm loss per day which is bothering me. But I'm buying the stuff from the local Wallmart. Any way to tell how fresh it is when I buy it (without taking a swig of it)? I have started storing it in the unfinished part of the basement for when my chlorine consumption gets low enough that it hangs around for more than a week.
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Re: Need help with my SLAM

    If it's Great Value bleach, there is really good turnover on those so they are almost always new. If it's the 10% stuff, sometimes there can be some older stuff, the date code is YY ddd where ddd is the # of days we are into the year.

    I'm pretty sure when you get done with your SLAM, you will be looking at a little less than a bottle/day.
    32K gallon Plaster - 1hp Hayward 2 speed Super Pump - Hayward S200 Sand Filter - TF100XL
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    Re: Need help with my SLAM

    I’ve decided I have to give up with the SLAM procedure for now. I’m still losing losing 3-5 ppm FC overnight, but at this point I’ve been SLAMming the pool for nearly three weeks and I haven’t noticed any improvement in the past week. Water is clear and I have <0.5 CC every time I test. I don’t like the amount of chlorine I have to put in, but the real killer is that nobody is really able to use the pool while I’m SLAMming. At least at lower chlorine levels, someone will be able to use it.
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Re: Need help with my SLAM

    Quote Originally Posted by skinpath View Post
    ... the real killer is that nobody is really able to use the pool while I’m SLAMming. At least at lower chlorine levels, someone will be able to use it.
    Why do you think this? It is safe to swim up to SLAM levels.

    It is of course your pool, but there is something in there consuming FC. If you don't kill it at, some point you really will have a pool people can't use.
    32K gallon Plaster - 1hp Hayward 2 speed Super Pump - Hayward S200 Sand Filter - TF100XL
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    Re: Need help with my SLAM

    I did a search of the thread and I don't see where anybody mentioned the light. In one of the pics I see alight and I am wondering if you have removed it. Many times that turns out to be the source of an extended SLaM.
    Bob - Palm Beach by San Juan Pools. approx 5000 gals., Pentair 320 cartridge filter (all new guts installed by me), Goldline SWG, 'New to me' Kreepy Krauly Sand Shark, Intermec 104 Timer Test kit: TF-100 w/Speed Stir

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    Re: Need help with my SLAM

    Quote Originally Posted by Mr Bruce View Post
    Why do you think this? It is safe to swim up to SLAM levels.

    It is of course your pool, but there is something in there consuming FC. If you don't kill it at, some point you really will have a pool people can't use.
    I guess my understanding of the SLAM process was that you wanted to keep the level as close to the SLAM level without going under the SLAM level. I did read that it was safe to swim up to SLAM levels (but without going over). I figured that meant it was only really helpful when you just finished SLAMming and were waiting to drift down to normal levels.

    Are you saying I can let people swim at a little higher than SLAM levels (since bathers will consume some of the chlorine), or that I can let people swim at up to SLAM level and then add more chlorine after they are done to get back up to SLAM levels? Either of those would certainly be helpful...
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Mod Squad tim5055's Avatar
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    Re: Need help with my SLAM

    Quote Originally Posted by skinpath View Post
    I guess my understanding of the SLAM process was that you wanted to keep the level as close to the SLAM level without going under the SLAM level. I did read that it was safe to swim up to SLAM levels (but without going over). I figured that meant it was only really helpful when you just finished SLAMming and were waiting to drift down to normal levels.

    Are you saying I can let people swim at a little higher than SLAM levels (since bathers will consume some of the chlorine), or that I can let people swim at up to SLAM level and then add more chlorine after they are done to get back up to SLAM levels? Either of those would certainly be helpful...
    Yup, they can use the pool up to and even a little over SLAM levels. Is ti the best idea, no. As you point out the swimmers are just going to increase chlorine demand, chlorine you really want killing stuff in the water.

    As an aside, as the chlorine levels go up it is really much harder on the swim suits than it is on the person/skin.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Re: Need help with my SLAM

    Quote Originally Posted by pabeader View Post
    I did a search of the thread and I don't see where anybody mentioned the light. In one of the pics I see alight and I am wondering if you have removed it. Many times that turns out to be the source of an extended SLaM.
    OK - I feel like an idiot but, surprisingly, this is good. I was about to write a reply about how I don't have a pool light, just two main drains. I decided to do a quick search on pool lights and - lo and behold - it looks like I probably only have one main drain...and one pool light. The irony is that I've been reading about pool lights being the problem in a bunch of threads and been wishing I could have a pool light so that at least I would have a possible source for my chlorine loss.

    Alright - I know what I'm going to do today.
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Mod Squad pooldv's Avatar
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    Re: Need help with my SLAM

    When is the last time you cleaned the filter? I would do that too if it has been a week or more. We swam daily while SLAMing last summer, CYA 70 and FC 28. Nobody even noticed except the guy with the TF-100.

    It is safe to swim when
    PH is 7.2 to 7.8
    FC is above minimum and up to shock level for your CYA, FC/CYA Chart
    And the water is clear
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    Re: Need help with my SLAM

    I had family come down last weekend, never been in my pool, they loved it and I asked them how much chlorine they "thought" was in the pool. less than 1 was the consensus because it did not smell like chlorine, they thought I was crazy when I told them it was at 32PPM. they could not even tell
    Pool: Intex 16x32 15000 gal, 2 speed 340042, Pentair CC320 Filter, CircuPool SJ45 Salt System, Intermatic PE653RC; Hot Tub: 650 Gal SWG Megachlor
    links: pool school * Recommended-Levels * SLAM * CYA chart * Test kits * How To Post Pictures * Poolmath * OCLT ** Support your website if we helped you :) **

  19. Back To Top    #19

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    Re: Need help with my SLAM

    I took out the pool light today and there was a bunch of crud behind it, including algae-looking stuff. I got into the pool to scrub out the edge of the light box. The inside of the light box was surprisingly clean (I assume because it doesn't have access to light - sunlight, that is), so all the crud must have been right at the junction of the light and the pool. I scrubbed all the surfaces well and put it back in. Hard to believe such a small focus would account for all of the FC loss overnight, but I'll keep my fingers crossed. Thanks for bringing up the light again pabeeder.

    Also, thanks to everyone for clearing up the swimming during SLAM thing. I'll definitely toss my kids in this weekend (with some goggles) and maintain SLAM levels.
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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    Re: Need help with my SLAM

    Sorry about the long hiatus, but had to start work and didn’t really have a lot of time to post and take care of the pool at the same time.

    I’m sure everyone is on the edge of their seat to learn how things went…

    Well, everything went great at the end! A few days after cleaning out the light the pool started to hold FC and it has been good since. We’ve been using it a lot and have had no problems either with the FC at shock levels or down to maintenance levels.

    In fact, we were guests at a local country club and the kids were commenting on how the pool there smelled “funny”. What they were smelling was combined chlorine from a pool that wasn’t trouble free!

    So, another win for Trouble Free Pool!
    In-ground (24íx40í) vinyl pool (~25k gallons), Pentair Clean and Clear Plus cartridge filter (Model CC420P - 150 gpm), Pentair 1.5 HP pump, Pentair MasterTemp 250 Heater. TF100 test Kit.

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