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Thread: Severe loss of chlorine - pool ate 24 lbs of shock in 48 hrs

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    Severe loss of chlorine - pool ate 24 lbs of shock in 48 hrs

    I have been battling a cloudy pool problem for weeks now. Had a bad mustard algae break out three weeks ago. Finally killed (had to use an entire bottle of Algamacine (sp) X)

    I have read the write up here on shocking your pool and have used the pool calculator to determine how much shock to put in but this seems very extreme.

    The readings I started off with.

    FC - .5
    PH - 7.3
    TA - 110
    CH - 280
    CYA - 90

    So the first day I put in 12 lbs of 68% shock... reading next afternoon... barely .5 (reading from pool store)
    Next day add another 12 lbs of 73% shock... reading that afternoon... .5 (this is from my own testing with my TF 100 kit that showed up via Fed Ex yesterday).

    This seems nuts to me... 24 lbs in 48 hours and NOTHING! What am I doing wrong here? What else should I be doing?

    Background... pool is 20x40 vinyl liner, 1 1/2 HP pump running 12 hours per day, Compu pool SWG 48 set on 100%, Hayward 425 cartridge filter (brand new this year). Water temp is about 85 degrees.

    Any help is appreciated... never had this problem in three years of owning the pool!
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    JasonLion's Avatar
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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    What kind of "shock" are you using? If you are using granular dichlor, this is not at all surprising, as dichlor contains CYA, and higher CYA levels need more chlorine, which raises the CYA level, which means even more chlorine, and so on. Even if it is not dichlor, with CYA at 90+, you often need really dramatic amounts of chlorine to kill algae.

    You should read in Pool School about fighting algae, and also think about replacing water to get the CYA level down to something more reasonable.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    WestSidePool's Avatar
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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Instead of using the packages of shock, I would invest in either liquid chlorine or bleach.
    You can raise your FC level very fast with those, and it wont add any additional chemicals into your pool.

    Also your CYA and TA seems high. With your SWG they should be lower. (information here).

    Follow this for the level of shock you need.
    You will need to keep your FC level up to shock level until you pass the over night FC loss test.

    Your SWG system should help keep the pool up to shock level so you may not have to add as much liquid chlorine/bleach.

    But to perform the overnight test you will have to shut it off.

    Again follow the instructions posted on how to shock your pool.

    If your still experiencing mustard algae, make sure you are shocking correctly for that.
    Eric

    IG 17x33 Grecian - Vinyl Liner (21k gallons), Hayward Pro-Grid DE 4820 filter, Hayward Super Pump, CompuPool SWG CPSC36, TF-100 Test Kit

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    ivyleager's Avatar
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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Let me say I hate mustard algae and feel your pain.

    What was the active ingredient in the Algamacine X? The most frequently used mustard algae products that I know of contain sodium bromine, which eats thru chlorine for several days.

    The "shock" chlorine product you are using, calcium hypochlorite, could also be causing some cloudiness. Maybe switching to bleach, sodium hypochlorite, can improve the water. It will at least not be adding anymore calcium to your water. I may be worth your while.

    Follow Jasons advice on the CYA/TA. What is your salt level? I noticed that wasn't in your listing.

    Lastly, how long do you run your pump/filter? I find increasing my run time during a time of crisis helps.

    Hope this helps.
    CaryB
    36 x 18 IG vinyl, 25K, 1 HP pump, sand filter
    1 skimmer, 2 returns, no main drain
    Old school: PoolSolutions test kit

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Good questions all... yes I read the SWG page and the shock level page and used those figures in the pool calculator to come up with amount of shock needed. I also read the instructions on shocking your pool.

    Jason... I am using Pool Life Turbo Shock... 73% available chlorine. I can' really tell from the packaging if it has a stabilzer in it or not.

    Should I switch Bleach instead?

    I have to add some water tonight so that should bring down the CYA naturally right?

    I did not measure my TA last night with the TF 100 ... will do it after I add the water and see.

    Added... on the salt level... 3200 ppm... need to add about 50 lbs.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    CaryB... not real sure what the active ingredient was... it was GLB's algae X product... pool store guy did state it had copper in it and not to swim within 24 hours of adding it... like we were going to anyway... duh
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    WestSidePool's Avatar
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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    I would just go ahead and switch to bleach or Liquid chlorine. They are the exact same thing. I prefer using liquid chlorine when I need to shock, becuase I am able to buy it cheaper in my area than bleach, and it has a higher concentration of sodium hypochlorite.

    Your CYA will go down when water is replaced by draining/splash out etc, but if your just replacing a couple of inches you may not notice much of a difference in the reading.
    Eric

    IG 17x33 Grecian - Vinyl Liner (21k gallons), Hayward Pro-Grid DE 4820 filter, Hayward Super Pump, CompuPool SWG CPSC36, TF-100 Test Kit

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    73% available chlorine sounds like calcium hypochlorite. Dichlor only has about 55% available chlorine. Looking on the bright side, at least you've not been adding more CYA, on the other hand it sounds like lots more chlorine will be needed.
    90k litres, outdoor in ground pool, concrete, painted (I hate paint)
    Sta-Rite 5P2R 1.5 Hp pump, undersized sand filter (needs upgrading).

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Quote Originally Posted by tdgray
    CaryB... not real sure what the active ingredient was... it was GLB's algae X product... pool store guy did state it had copper in it and not to swim within 24 hours of adding it... like we were going to anyway... duh
    From the MSDS sheet I found online, this product doesn't have cooper:
    Product Name: GLB Algae-X
    Chemical Name: Poly(oxyethylene(Dimethyliminio)Ethylene(Dimethyliminio)Ethy lene Dichloride)

    Which sounds suspiciously like the polyquat60% we recommend here as a weekly preventative. The one website I found for GLB Algae-X states it's a 30% polyquat. http://www.poolmerchants.com/glb-qt-alg ... 71100.html Take home point: know thine ingredients.

    Just to switch things up, change to bleach so you can absolutely know that the Turbo Shock calcium hypochlorite isn't continuing to cause some cloudiness. (I use 73% calcium hypochlorite for maintenance on occasion as well as when I need to shock).

    Are your cartridges clean?

    Hope this helps.
    CaryB
    36 x 18 IG vinyl, 25K, 1 HP pump, sand filter
    1 skimmer, 2 returns, no main drain
    Old school: PoolSolutions test kit

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Okay... so I have this from all of your input and the pool calculator

    Switch to bleach or liquid chlorine ( I assume as in the liquid from the pool store) instead of granulated shock.

    Pool calculator suggests the following

    Replace 11 % of the water to lower CYA to 80 (I will take another reading on the CYA tonight before I put more water in)
    To raise FC to 30 I need 16 gallons of 6% bleach (where I am going to find that much bleach in one place is beyond me)

    If I was to use the liquid chlorine from the pool store what... who many gallons would that be... I assume it is more concentrated that 6% bleach?

    Thanks to all... CaryB thanks for the info and yes I know I should know my ingredients... will be more dilligent in the future. Cartridges are clean as far as I can tell (no pressure rise)
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    ivyleager's Avatar
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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    The PoolCalculator will do the calculations, you just enter the percentage strength. The measurement shows up in the top header when you curser/mouse over the field for detail.
    CaryB
    36 x 18 IG vinyl, 25K, 1 HP pump, sand filter
    1 skimmer, 2 returns, no main drain
    Old school: PoolSolutions test kit

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    I've had to fight through a mustard algae problem before. I would assume your Algamacine X did not do the job and shock with liquid chlorine at mustard algae levels.

    Could you post some more information about your pool? Is it in ground or above ground, vinyl or plaster, etc.

    Also, how are you measuring your chemicals?
    Built in 1957 44,000 gallon in-ground, Wet Edge Primera Stone in Sky Blue, Intelliflo VF Pump, 600 lb. Pentair Triton II TR-100 Sand Filter, CircuPool RG 60 Plus SWG, TF-100 test kit
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    WestSidePool's Avatar
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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Quote Originally Posted by tdgray
    If I was to use the liquid chlorine from the pool store what... who many gallons would that be... I assume it is more concentrated that 6% bleach?
    (no pressure rise)
    Pool store prices are typically high for Liquid Chlorine, but normally they stock it at a concentration of 12%, at least the ones around me do.

    I see you're in Ohio. I buy mine from either Kroger or Meijers. They both sell a 4 case of liquid chlorine (1 gallon each) at 10% strength. Kroger is/was $10.99 and Meijers is/was $11.99 (It can be found in the seasonal sections). They normally stack them on Skids, so you should be able to find enough if you go this route.

    For bleach, check Walmart, etc.

    Again, use the pool calculator and enter the the strength % in to the field, along with the size to determine the amount you need to get up to shock level, then buy extra to make sure you can keep your FC up until everything has been killed.

    Good luck.
    Eric

    IG 17x33 Grecian - Vinyl Liner (21k gallons), Hayward Pro-Grid DE 4820 filter, Hayward Super Pump, CompuPool SWG CPSC36, TF-100 Test Kit

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    okay just came home with 18 gallons of bleach... decided to test the FC before I added any to what is there... using my TF100... same thing I used last night... I now get a 14.5 FC reading.

    How is this possible? I added the pool lite 75% stuff at noon yesterday... read it last night both stick test and TF100 test and there was NOTHING.

    Now I am thoroughly confused.

    I will recalc the pool calulator for my newfound condition
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Did you add the needed salt?
    23,000 gallon in ground pool with rock waterfall and spillover spa, Aqualink control system, Polaris 380 cleaner, Purex Triton Clean&Clear Plus cartridge filter. Located in The Woodlands, Texas.

    Pool owner since Nov 2008, Trouble Free since April 2009. Happy to help when I can.

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    nope... not yet nor have I added water.

    re-tested... about the same result... 12.5. - 13... CC about .5

    PH is low 7.2

    TA is 80

    CYA is 70 ish
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    added 12 gallons of 5.7% bleach trying to achieve a FC of 28 per the shocking guidelines... will test for overnight loss and report back...

    SWG is off
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

  18. Back To Top    #18

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Okay much better this morning... thanks to all... last night late... FC = 30... this morning FC = 28 and that was with adding quite a bit of water.

    Might have this thing on the run.... will raise PH later today. Leaving the SWG off for today... do the overnight check tomorrow.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

  19. Back To Top    #19

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    Mustard algae is very hard to kill. It is much easier to maintain proper Cl levels to avoid an outbreak of mustard algae. My experience says that you will adding sufficient amount of hypo to prevent the mustard algae from getting worse but that your Cl level was insufficient to kill the mustard algae.

    If your testing of the over night Cl test shows that you have algae then you must hit it hard and fast. If you attempt to maintain a high Cl level but below the required shock level you can add Cl all season and never have a clear pool.

    A note for optimism. We added borax and started testing with the TF-100 test kit 3 years ago. We have not gone to a pool store since and have not had any algae problems. To avoid algae conduct your own tests, use the BBB method, and maintain the proper water balance.
    30,000 gallon gunite in-ground with a spillover spa, Diving board and water slide
    Hayward 1 HP Super II filter pump, Hayward 24 " Sand Filter Pro Series using zeolite media
    Polaris 380 cleaner with ¾ HP booster pump, Hayward Heatmaster pool heater, AutoPilot DIG-220 Power Supply SC-60 cell
    Testing with the TF-100 Test Kit

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    Re: Severe loss of chlorine - pool ate 24 lbs of shock in 48

    I think we are in good shape to start clearing... No FC loss overnight. Turned the SWG back on. Added PH up (had some on hand already)this morning... reading was 7.2.

    I think I see some clearing of the cloudyness already. Thanks to all.

    And yes Steve... I think I have made my last visit to the pool store for chemicals. True believer in the BBB method.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 1.5hp Dynamo pump. 24" Pentair Sand Dollar Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit
    You can stop SLAMing your pool when you pass the OCLT (You lose 1ppm or less FC overnight, & You have .5ppm CC's or less) & your water is clear.

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