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Thread: When to slam

  1. Back To Top    #1

    When to slam

    I've been reading through some of the forum topics and have a few other questions that I couldn't answer.
    On my drop test my readings are
    Combined Cl test .6
    ph 8.2
    I'll have to look up the other readings I had but I know the stabilizer was okay and alkalinity was high.

    I just moved in a month ago, the pool has always been sparkling clear even though the cl readings have always been too low. Ph has always been too high. I read that you need to adjust pH first because it makes the cl more effective (I use the pool Cl from home depot). The pool had a ph of 8.2 when I first started. I backwashed and added DE. I've been slowly adding acid (about a half gallon a day when the filters are running) and got it to 7.6 for a few days, I added Cl after that.

    My CL went up to normal levels after that, but decreased a few days later. At the same time pH again began to rise and I kept adding muriatic acid (also from home depot) but the last week I've added probably 2 gallons and the pH always goes back to about 7.8 after a day. My spa waterfalls into the pool, I read on your forums that can cause the pH to rise but I can't control that part of my pool. It almost seems like there is something else going on that is killing my muriatic acid dosages and also with the high levels of stabilizer present I wouldn't think my Cl levels would go down so quickly.

    I read here that normally you slam the pool when the pool is green or has an organic problem, my pool does not seem to follow those problems and even without the normal Cl readings the pool rarely has any algae growth. Because the chemicals seem to not be helping much, should I slam it with liquid chlorine anyways? I just don't want to keep buying chemicals if I need to slam it first.

    The pool does have a SWG but it is no longer functioning, there is still salt in the pool and I am planning on getting a new SWG soon but don't want to empty the entire pool right now as it is at 30 gallons of water.
    Chris
    30k gallon
    IG, plaster
    DE filter
    I'll have to look up the pump specs in the am
    Pool was built approx 1989
    has connected spa with waterfall, SWG (not presently functioning)

  2. Back To Top    #2
    Smykowski's Avatar
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    Re: When to slam

    Welcome to the forum!

    First, in order to make specific recommendations for your pool we need a full set of reliable test results. "OK" and "high" and "in range" are meaningless to us. We also don't trust test strips or pool store test results, so you will get a lot of people chiming in after me to tell you to buy a good drop-type test kit, either the Taylor K-2006 or TF100.

    As for general discussion, if your water is clear, you don't need to SLAM it. SLAMing a pool is only necessary if you have visible algae or if an overnight chlorine loss test shows something living in the water. You can only perform the OCLT with a good kit, so if you're going to do that, wait until the kit arrives.

    pH rise can be from a couple things. Curing plaster from a brand new pool would do it, but I'm going to assume that your pool is more than a year old. Aeration from the waterfall will have a big effect. Anyone with water features just has to live with climbing pH and regular acid additions. Assuming the TA is actually high, that will also contribute to pH rise. Finally, a SWG will force the pH to go up as well. SWG users are also pool owners who have to live with regular acid additions. Some of that pH rise can be tempered, some can't, but with our methods, you'll at least be able to predict it and know there's nothing wrong with your pool.
    33' round, 23,000 gal AG vinyl , 1HP 2spd PowerFlo Matrix downsized with 3/4HP impeller (X2), Hayward S180T 150# sand filter (X2), Hayward H250 NG heater Pool Store year 1 - $850 for 2 months; Pool Store year 2 - $440 for 2 months, TFPC year 1 - $170 for 4 months; TFPC year 2 - $95 for 4.5 months
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  3. Back To Top    #3
    Mod Squad zea3's Avatar
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    Re: When to slam

    Hi, Welcome to TFP! We really need to see a complete set of test results before we can give you an idea of what may be going on in your pool. We need to see results for FC, CC, CYA, CH, TA, and pH.
    TFP Moderator
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    Vogue 21' round AG, Pentair 1 hp 2 speed pump, 36 sq ft DE filter, Hayward S180T 150# sand filter, Houston, Texas
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  4. Back To Top    #4

    Re: When to slam

    Quote Originally Posted by freediver
    I've been reading through some of the forum topics and have a few other questions that I couldn't answer.
    On my drop test my readings are
    Combined Cl test .6
    ph 8.2
    I'll have to look up the other readings I had but I know the stabilizer was okay and alkalinity was high.

    I just moved in a month ago, the pool has always been sparkling clear even though the cl readings have always been too low. Ph has always been too high. I read that you need to adjust pH first because it makes the cl more effective (I use the pool Cl from home depot). The pool had a ph of 8.2 when I first started. I backwashed and added DE. I've been slowly adding acid (about a half gallon a day when the filters are running) and got it to 7.6 for a few days, I added Cl after that.

    My CL went up to normal levels after that, but decreased a few days later. At the same time pH again began to rise and I kept adding muriatic acid (also from home depot) but the last week I've added probably 2 gallons and the pH always goes back to about 7.8 after a day. My spa waterfalls into the pool, I read on your forums that can cause the pH to rise but I can't control that part of my pool. It almost seems like there is something else going on that is killing my muriatic acid dosages and also with the high levels of stabilizer present I wouldn't think my Cl levels would go down so quickly.

    I read here that normally you slam the pool when the pool is green or has an organic problem, my pool does not seem to follow those problems and even without the normal Cl readings the pool rarely has any algae growth. Because the chemicals seem to not be helping much, should I slam it with liquid chlorine anyways? I just don't want to keep buying chemicals if I need to slam it first.

    The pool does have a SWG but it is no longer functioning, there is still salt in the pool and I am planning on getting a new SWG soon but don't want to empty the entire pool right now as it is at 30 gallons of water.
    I have all my water features turned off and I need to add about a half a gallon of acid a week. In the past I was adding half a gallon every two days with the waterfall on. (my pool is 20K so much less water than yours). When my TA was higher the pH would go up faster as well. Eventually I added enough acid to lower the TA to about 60ish.

    Even with stabilizer you will use chlorine. I add about half a gallon per day of bleach into my 20K pool. That is around 3ppm per day. The equivalent for you would be around 136 oz or about 3/4 gallon/day.

    As the other posters mentioned get a good test kit, test your water and post the results.
    17,800 gallon, IG pool, 595 sq feet (17x35x4.5 avg rectangle), Hayward 525 cartridge filter, diamondbrite, 2 hp 2 speed hayward tristar filter, Stenner 45mhp10 automatically chlorinating

  5. Back To Top    #5

    Re: When to slam

    Wow Thank you for the replies. I had no idea that the pool would require so much chlorine and acid! I turned my spa way down so it only trickles into the pool now and I retook my readings today.

    Free Cl less than .6
    Br less than 1.3
    combined cl less than .6
    pH 7.8
    alkalinity 130 ppm
    hardness 1000
    stabilizer 100

    I will go by the recommendations of the pool calculator and add the acid first, then the chlorine tonight. I'll let the pool settle for a day and then do the overnight chlorine loss. Any other things I should look out for or consider? The pool plaster is older and was resurfaced with some sort of material that resembles gray granite, I'm not sure what it is but it was done about five years ago.
    Chris
    30k gallon
    IG, plaster
    DE filter
    I'll have to look up the pump specs in the am
    Pool was built approx 1989
    has connected spa with waterfall, SWG (not presently functioning)

  6. Back To Top    #6
    Mod Squad jblizzle's Avatar
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    Re: When to slam

    Welcome to TFP!!!

    I will reiterate that you need to get one of the Recommended Test Kits.
    Then likely you will need to replace water to lower the CYA into recommended levels.
    Then you will need to Perform the Overnight Chlorine Loss Test to see if something is growing in the water consuming your FC even though you have no visible algae.
    If you fail, you then need to go through the SLAM Process.

    There is no "letting the pool settle for a day". You can test an hour after adding the chlorine. Also, you need the FAS-DPD test to accurately do the OCLT.
    Jason, TFP Moderator
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  7. Back To Top    #7
    Jeetyet's Avatar
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    Jul 2012
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    Re: When to slam

    What test kit are you using at present?
    "The early bird might get the worm, but its the second mouse that gets the cheese." ~ W. Rian Adams
    .
    Relative's IG Vinyl | 16x32 | ~18,600 gals | Hayward 3/4hp Pump | Hayward S244T Filter | Pentair Model 300 Chlorinator (not used) | Polaris 180

  8. Back To Top    #8
    Charlie_R's Avatar
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    Re: When to slam

    Looks to me to be the HTH (Walmart) 6-way test kit. A good start, but still not good enough for the OCLT.
    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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