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Thread: Converting to SWG after replaster job

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    Converting to SWG after replaster job

    We just finished having our pool replastered and are still waiting for the Aquarite system to get here (40K) and had read that we needed to dissolve all the salt into the pool prior to turning on the Aquarite system.
    We were getting ready to purchase some salt and then read where we should wait 10-14 days before adding salt on a replaster to allow for the plaster to cure. We are filling the pool now with well water (started day of plastering) and am
    wondering what we should do to the water for the next few weeks while we allow the plaster to cure more.
    Should we put in some chlorine in the mean time? Will this need to be drained out and refilled to convert over the salt when that time arrives?
    Any input or advice?
    The pool is a freeform design and we are timing how long it takes to fill with 2 hoses and then want to time how long it takes to fill a 5 gallon bucket with water to try to compute just how much water the pool holds, any better ideas on how to calc the volume?
    Thanks,
    Phil

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    Re: Converting to SWG after replaster job

    JamesW provided this for me in another thread. You should check it out.


    As far as calculating the volume, I would just guestimate using the guestimation calculator at the bottom of the pool calculator. I've read on TFP somewhere, it's not rocket science. Treat your pool according to the guestimated numbers and adjust as necessary.

    I've been reading this forum for almost a year, but only recently got my pool. The pool calculator and all the numbers and chemicals were pretty hard for me to grasp before I actually started doing it. It makes much more sense now.

    When we were designing our pool, I had many people telling me I should go with a salt water generator, because it is much less maintenance. I have found so far the only thing a SWG would aleviate, is the manual addition of what will amount to less than a gallon of bleach a week. TA & Ph still need to be monitored & maintained weekly.

    TA is very important, and my new plaster pool provided some challenges. Evidently the calcium (or something) in the plaster causes TA to rise, which if it isn't kept in check will make your Ph difficult to control, which will cause premature scaling (my heater core is ruined). So..... check your TA and keep it in check.
    Custom Cloud shaped 19'x35' - Raised Spa 6' diameter
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    JasonLion's Avatar
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    Re: Converting to SWG after replaster job

    Welcome to TFP!

    You don't want to add salt for the first 30 days after fresh plaster is applied. What you do want to do is to keep a close eye on the PH and lower it as needed to keep it below 8.0 (unless the pool builder tells you otherwise).

    Trichlor tablets are very handy to use when starting up fresh plaster, they add chlorine and CYA gently and slowly and help keep the PH from going up quite so much.

    The link thunderkyss provided has lots of great information in it.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Converting to SWG after replaster job

    I just wanted to add some updates.
    I had my water tested and bought a new brush, pole etc to try to catch up on what I should be doing to the new pool and plaster job.
    I was told to add one gallon of muratic acid to the pool, and also to put in some water clarifier and also some chlorine pouches to hold me over until the salt system comes into play.
    The pool plaster color is a dark blue and I've noticed some "silt" light colored starting to settle on the surface, I am trying to brush it back to get down to the dark color but it seems that some areas are not giving up the light color silt.
    I have not added any of the acid, or other chemicals at this point and am wondering if there is something I am missing as far as steps?
    My Ph was 8.4 I believe with well water.

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    JasonLion's Avatar
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    Re: Converting to SWG after replaster job

    It is critical that you keep the PH under 8.0 at all times. If you don't you can get calcium scale on the pool, which is unsightly and difficult to remove. That is probably what the "silt" you describe is.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Converting to SWG after replaster job

    I just added 1 gallon of Muratic acid to estimated 24,000 gallon pool. should this bring the PH down to 8.0 or lower from a start of 8.4?

    If the "silt" looking stuff that is covering the surface of the pool is calcium scale will lowering the PH allow the scale to come off easier?
    If it does not come off easily, should I drain the pool and acid wash the walls, floors again to be able to get through the "silt" covering?
    If not, are there any suggestions on getting this stuff off easily?
    Thanks for all the info already,..
    Phil

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    JasonLion's Avatar
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    Re: Converting to SWG after replaster job

    SInce the PH test probably only goes up to 8.4, and reports higher PH levels as if they were 8.4, your actual PH might be quite a bit higher. Thus, it is impossible to say what your PH is right now without testing it again.

    Very mild calcium scale may well come off with lower PH and brushing. If it is more severe you may need to drain and acid wash. Sometimes you can get it off with a pumice stone, though that is impractical if it covers a large area.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Converting to SWG after replaster job

    Okay,..
    I'm thinking to put in the 2nd gallon of muratic acid and then test again in the morning.
    It does cover a large area, about 80% of a 24,000 gallon pool.
    Can I get into trouble putting too much acid in trying to lower the PH,.. Also if I were to drain and acid wash, is there a way to get it all over with prior to refilling or does this go on for weeks needing to brush the surface?

    Also checked water and the best of my ability I show:
    100 ppm total Hardness
    0 total chlorine
    0 free chlorine
    7.2 PH
    80 PPM total alkalinity
    0 PPM cyanuric acid

    that is with adding 1 gallon of muratic acid, about 1.5 hours ago.
    Phil

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    frustratedpoolmom's Avatar
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    Re: Converting to SWG after replaster job

    You want to avoid draining and acid washing if you can.

    Target 7.0 or 7.2 using the pool calc, and test every 2-3 hours and add more acid as necessary to bring it down. If the scale is newer and is going to dissolve this way you should see it work fairly soon but yes, you may need to brush for a few weeks. Good bicep workout
    Helpful links: Pool School; CYA/Chlorine Chart
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    Re: Converting to SWG after replaster job

    I had to put about 7 gallons of Muriatic Acid on the pool to get the scale to let loose.
    Got up this morning and most of it was actually gone without brushing although there are a few areas that seem not to be reacting even to brushing at all.
    I did notice that when I brought the brush up from the side walls there was occasionally a little "blue" color coming from the plaster itself, hope my mix is not too hot and doing some damage.
    I did pick up about 8 boxes of Borax at Wal-Mart as I figured I would need this to bring the PH back up after getting the walls cleaned. I was not able to find any info on how much I could
    expect to add to get it back into balance. Also should I bring it back up now, closer to 7PH or leave it where it is and continue to clean the walls.
    I am using a soft brush and thought getting a stiffer brush, or even what looks like a fine wire brush I saw at the pool supply store.
    Again, thanks for allowing me not to drain and do a acid wash.
    Phil

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    JasonLion's Avatar
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    Re: Converting to SWG after replaster job

    You are being too aggressive, which can cause damage. You need to be very cautious when lowering the PH, and never that dramatically. It is much better to err on the side of not taking off all the scale than risk thinning the plaster out in some area and using up most of it's normal lifetime. Low PH can also damage the pool heater, if you have one.

    You should raise the TA first with baking soda up to around 60 to 70, give it an hour to mix in, then retest the TA to see if you hit your target and readjust as needed. Then retest the PH and adjust the PH to around 7.0 to 7.2.
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    Re: Converting to SWG after replaster job

    Okay,.. of to get Baking Soda,..Thanks for the info again,
    I do not have a heater and was running the pump with skimmers initially and am now pumping through the main drain only for a bit.
    Any idea as how much to Baking Soda to add initially, 3 boxes ?
    Phil

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    Re: Converting to SWG after replaster job

    I calculate about 20 lbs of baking soda, but the exact amount required depends on how low your PH actually went and how much scale/plaster has been dissolved, so it could be more or less than that. The best thing would be to get a current TA reading and calculate from that, or failing that, try 10 lbs and see what happens.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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    Re: Converting to SWG after replaster job

    PH is 6.2 , or lower, if that is possible as the color seems to be even lighter than the lowest limit.
    Also the Total Alkalinity is 0
    Will buy some Baking Soda and try 10 lbs and go from there every hour or so.
    What are the thoughts on a stiffer brush and or a fine metal wire brush at the pool store, should this help with the few remaining light areas?
    Phil

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    JasonLion's Avatar
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    Re: Converting to SWG after replaster job

    You don't normally want to use a wire brush, or mixed wire nylon, during the first year.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
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