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Thread: Does SLAM at 7.8 pH work?

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    Does SLAM at 7.8 pH work?

    Would like to get through the rest of the season without buying any muriatic acid if pH level is no biggie. Vinyl liner pool, pretty sure I have a little mustard algae. Pool hasn't really been used too much the last couple summers, and this summer I was pretty neglectful - chlorine dropped too many times. Never any significant algae outbreaks, but a couple spots have come back 3 times now within a few days or a week of SLAM.

    I never worried about high pH during shock before, and never had any trouble... but thought I'd ask before running chlorine up to mustard shock levels.
    25,000 gallon 18x36 vinyl inground, sand filter, been doing this a few years now and feel like I have a decent handle on it.

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    TFP Guide


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    Re: Does SLAM at 7.8 pH work?

    Hello,

    It will work, BUT you are on the highest end of the recommended range. Have you checked your other levels for your TA, CSI, and CH-with the vinyl liner this isn't as much of an issue for you but if the levels are all too high, it could be.

    As I'm sure you are aware it is advisable to lower your pH to 7.2ppm before increasing the FC level because the readings won't be accurate once the FC level reaches 10ppm, or higher.
    The higher the pH the less active your chlorine will be. Also if you have metals in your pool, the higher pH levels, especially if it raises higher during the SLAM from aeration, etc. can cause scaling. Like I said before you don't have as much issue because of your vinyl liner, but you do have to consider your equipment as well.

    Plus, are you planning on swimming at all during the SLAM because the pH could climb to an unsafe swimming level, and you wouldn't even be aware it had. Of course, the final decision is yours whether to SLAM with your pH at that high of a level, or not, but I personally wouldn't do it, and wouldn't recommend that you do it either. Others with more experience may come along and be able to offer you better advice, so if they do, please don't hesitate to take their more experienced opinion and suggestions over mine.

    But regardless of what you decide, I hope you get your algae issue cleared up quickly.

    I hope this helps. Have a wonderful night.
    24' Round x 4.5 ft deep AGP (15,200 Gallons), Vinyl Liner, Hayward Vari Flo XL Sand Filter- (model SP0714T1),
    TFTestkits , PoolMath , Pool School, RECOMMENDED LEVELS, SLAM & the Chlorine/CYA CHART. Support this Site! TFP Totally Rocks.

  3. Back To Top    #3

    Re: Does SLAM at 7.8 pH work?

    pH just doesn't seem to drift in this pool, so that's not a concern... but I was not aware that chlorine was less effective at higher pH.

    Actually, I hadn't checked TA or CH since I opened... after checking them for a couple of seasons I found that my pool is pretty simple compared to some of what I've read on here... TA never gets out of range, CH only got in upper range when cal-hypo was chlorine source. Checking them this morning, TA is 100, CH 80. So that's all good.

    Guess I will pick up a little muriatic acid and lower as suggested, as chlorine certainly needs to be effective as possible during SLAM for mustard. Thank you.
    25,000 gallon 18x36 vinyl inground, sand filter, been doing this a few years now and feel like I have a decent handle on it.

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    TFP Guide


    Join Date
    Jul 2015
    Location
    Kentucky
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    Re: Does SLAM at 7.8 pH work?

    Sounds like the best plan of action to me. Have a safe Labor Day weekend. .
    24' Round x 4.5 ft deep AGP (15,200 Gallons), Vinyl Liner, Hayward Vari Flo XL Sand Filter- (model SP0714T1),
    TFTestkits , PoolMath , Pool School, RECOMMENDED LEVELS, SLAM & the Chlorine/CYA CHART. Support this Site! TFP Totally Rocks.

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