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Thread: Testing "during" a heavy rain period?

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    Join Date
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    Testing "during" a heavy rain period?

    Hi all,

    How carefully do you all check and balance your water during a long period of heavy rain?

    It's been raining in my area for a good week or more and during that time I've seen my chemicals literally go down the drain.

    My salt levels seem to be just hanging in there and all other stats are generally OK at this stage. Chlorine is the main thing I'm watching so I stay on top of algae. The thing I'm seeing swing the most is pH which as has been discussed in another thread is most likely due to the heavy rain aerating the water.

    So what to do... keep adding acid every couple of days, or do most people just wait until the rain stops before re-balancing the water?

    Thanks,
    Steve
    37000 litre, concrete, pebble, Viron P300 pump, Hurlcon VX7T SWCG, Viron CL-400 Cartridge filter, Solar heating, Pandora Smart Robotic cleaner

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    Re: Testing

    You can get a sample from deeper in the pool and bring it indoors. A well lit room will have to suffice for testing but should be adequate so you can figure out what your pool needs.

    You might think about boosting the FC level with some bleach but I would expect the salt cell's pH rise and the rain to mostly cancel each other.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Re: Testing

    In my experience, heavy rain can really affect alkalinity levels. Check this before treating PH, or PH may need adjusting a second time if you adjust alkalinity.

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    Mod Squad Bama Rambler's Avatar
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    Re: Testing

    I stick to my regular schedule whether it's raining or not. In fact when it rains a lot, I test more often because it will affect the FC most.

    Here, where we get 5 to 6 feet of rain a year I haven't seen it affect the TA much, if at all. My TA stays between 70 and 80 ppm all year. It all depends on where you're located and what the rain brings with it I suppose. If you use the chemicals and methods in Pool School you should be able to regulate your pool pretty evenly, even when it rains.
    Dave J. TFP Moderator
    24' x 52" Round AGP. 2hp/¼hp SPL Power-Flo 2-speed pump. 200sqft Waterway Cartridge Filter. 45MHP2(3GPD) Stenner Peristaltic Pump
    Pool School ----- Pool Math ----- TF-Test Kit

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    Testing "during" a heavy rain period?

    Thanks for the replies. Consensus so far seems to be to continue as usual during extended periods of rain. The only thing I'm needing at the moment is acid, so I suppose I'll just keep on adding it as usual. TA is coming down a bit but it could do with that anyway. My SWCG is keeping the chlorine levels up nicely. It helps having no sun and no swimmers. The rain seems to be easing finally so I'll check everything else in the next day or so and add what's needed then.
    37000 litre, concrete, pebble, Viron P300 pump, Hurlcon VX7T SWCG, Viron CL-400 Cartridge filter, Solar heating, Pandora Smart Robotic cleaner

  6. Back To Top    #6

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    Re: Testing

    Just remember to take your water sample from fairly deep in the pool to get a more accurate sample. Near the surface will be lower levels of everything due to the dilution by rain.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

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    Richard320's Avatar
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    Re: Testing

    Quote Originally Posted by PoolGuyNJ
    Just remember to take your water sample from fairly deep in the pool to get a more accurate sample. Near the surface will be lower levels of everything due to the dilution by rain.

    Scott
    Agreed. To do this, get a piece of PVC pipe. Plug the end with your thumb, plunge it in the pool, release your thumb, water will rise in the pipe. Clamp your thumb over the end, and quickly swing the pipe over a cup and release the water.

    I do this all the time - you can test water when it's really cold and you're wearing long sleeves! Get your sample and carry it somewhere where you can sit and test comfortably. And dry, in your case.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

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    Puffin's Avatar
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    Re: Testing

    Quote Originally Posted by Richard320
    Quote Originally Posted by PoolGuyNJ
    Just remember to take your water sample from fairly deep in the pool to get a more accurate sample. Near the surface will be lower levels of everything due to the dilution by rain.

    Scott
    Agreed. To do this, get a piece of PVC pipe. Plug the end with your thumb, plunge it in the pool, release your thumb, water will rise in the pipe. Clamp your thumb over the end, and quickly swing the pipe over a cup and release the water.

    I do this all the time - you can test water when it's really cold and you're wearing long sleeves! Get your sample and carry it somewhere where you can sit and test comfortably. And dry, in your case.
    Wow, what a great idea! I'm going to have to try this. How big a piece of PVC do you use?
    19,600 gal, Vinyl, Grecian L, StaRite Dura-Glas 1 HP pump, 3/4hp booster, Pentair Clean and Clear 420 Cartridge filter
    The Pool Cleaner 4x, PoolSkim

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    Testing "during" a heavy rain period?

    Yeah fantastic idea Richard.
    37000 litre, concrete, pebble, Viron P300 pump, Hurlcon VX7T SWCG, Viron CL-400 Cartridge filter, Solar heating, Pandora Smart Robotic cleaner

  10. Back To Top    #10

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    Re: Testing

    A small pitcher, upside down, arm deep, then turned right side up is fine for the sample to come inside and test.

    Scott
    Owner of - PoolGuyNJ LLC
    Expert Pool and Spa Repairs, Renovations, and Augmentation. Helping people decide what is the right gear for meeting their needs. Expectations Set, Expectations Met, No Surprises.

  11. Back To Top    #11
    Richard320's Avatar
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    Re: Testing

    Quote Originally Posted by Puffin
    Wow, what a great idea! I'm going to have to try this. How big a piece of PVC do you use?
    I bought a 4' piece of 1/2" PVC at Lowes. It was cheap, don't remember exactly how much.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
    Troublefree does not mean Maintenancefree. It's like brushing your teeth: You can spend a couple minutes a day and pennies a week or go to the dentist once a year and spend several thousand dollars.
    A pool is like a pet - you have to feed it every day, even the days you don't want to play with it!

  12. Back To Top    #12

    Re: Testing

    Your rain OUGHT to have near 0 TA, 0 CH, 0 FC, and 0 CYA (although I guess dust could affect the TA and CH values). So bear that in mind as you monitor pool water values. If TA and CH and CYA were on the low side, pay attention. Each of those is corrected by adding the individual chemicals as needed, per the Pool Calculator.

    My pool tends to run high TA due to the tap water TA levels, so rain lowers the TA and the pH tends to stabilize up to a point. Lower than about 70 TA and the pH gets unstable in my pool (suddenly running too high or too low, it seems). Tap water corrects this in my pool but baking soda is faster.

    As the CH lowers, I get to use cal-hypo for chlorine which is a bit cheaper than bleach when bought in the huge buckets. With SWG you would probably just add calcium, unless you had reason to shock the pool.

    As CYA lowers, I get to use trichlor tablets in the feeder which frees me from bleach and acid as long as my TA is not too low. With SWG you would just add CYA.
    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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