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Thread: Decision Making Time. Drain it or not?

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    Decision Making Time. Drain it or not?

    I am two days into the new season and find myself already at a cross roads. First I must preface by saying I don't have a full set of readings to post at the moment mainly because I have added borax and bleach this morning.

    I have a number of reasons to suggest draining the pool completely and starting over vs. investing more money trying to make this work. I have a 9000 gallon fiberglass pool that I fill with well water. (free water) This is my 4th season of owning the pool and up until last season, it has been very simple to maintain crystal clear water. Since last year, I have had a hard time keeping the water clear and also keeping pH up.

    Ever since I got my TF100 kit a couple years ago I have been completely unable to get my CYA to acceptable levels no matter what i try. It has never read below 100 even with 80% drains of the pool. I have done that twice and immediately after the refill my CYA was still over 120.

    So even though I would like to drain and start over, I have past experience which tells me I won't have any success. I would like to do a 100% drain but I am afraid of doing that to a fiberglass pool as there are so many warnings out there against this.

    I have even tried draining while filling hoping I could "flush" the remaining CYA out of the water while down to the last 20%. But my cya never changes substantially. So right now I am thinking....should I go ahead and try the drain approach again and risk seeing no results as the previous two times or maybe I should just discontinue dichlor and trichlor and hope the refill water will eventually take over and eliminate the cya contaminated water?

    Currently my water issues are that the water is still somewhat cloudy 50+ hrs after opening. I can barely see the bottom. Also my pH continues to read low (6.8) and my TA continues to read high (220) and of course the high cya. FC was 22 and CC was 0 last night and I added 2 btls of bleach this AM because according to the Pool calculator I need to reach a shock level of 39.

    I will post full results later.
    10,000 gallon
    Viking Freeform Fiberglass Inground Pool. FNS Plus DE Filter Pentair Challenger .75hp pump

    NC KANSAS44

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    linen's Avatar
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    Re: Decision Making Time. Drain it or not?

    Quote Originally Posted by Thinkly
    I have even tried draining while filling hoping I could "flush" the remaining CYA out of the water while down to the last 20%. But my cya never changes substantially. So right now I am thinking....should I go ahead and try the drain approach again and risk seeing no results as the previous two times or maybe I should just discontinue dichlor and trichlor and hope the refill water will eventually take over and eliminate the cya contaminated water?
    Your past infatuation with the trichlor and dichlor put you in this ultra high CYA position that you are in. Post your test results (though I am assuming it is ready 100 ppm cya +) and get ready to do another partial drain and refill. CYA doesn't just show up, you put it in there and now you must get it out!

    Quote Originally Posted by Thinkly
    So even though I would like to drain and start over, I have past experience which tells me I won't have any success.
    Again, if you do not put it in there via constant use of trichlor and dichlor, you would not be in this position now. CYA does not put itself in you pool water by itself.

    Others will need to comment a full drain, but my understanding is if you have a high water table it could cause you pool to pop. Partial drain (or multiple cycles of it) may be your best bet since your water is cheap.
    TFP Expert who uses Pool School and my TF100 test kit along with PoolMath for my: Round 11K gallon AGP with deep end, 20" sand filter, Matrix 1hp 2spd, 6 2ftX20ft solar panels (and solar cover!), Intex SWCG (copper bars disconnected) and a Rubadub hot tub (chlorine). The SLAM process is not finished until: 1. CC < 0.5 ppm, 2. An OCLT < 1.0 ppm and, 3. The water is crystal clear.

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    Ohm_Boy's Avatar
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    Re: Decision Making Time. Drain it or not?

    I'd refrain from a 100% drain, opting instead for one or more 75%-80% drain/fill cycles. That you've already made such drain/fills and still have immeasurable CYA places the original CYA level at absolutely mind-boggling amounts. What have you been feeding that pool? [Edit - Sorry, I've now seen what you've been feeding it. Please disregard that question.]
    I'm pleased to see that you are using bleach now, but you are wasting chemicals until you get that CYA down. Realize that if you continue to use Trichlor and/or Dichlor, you are just adding more CYA back into the water from which you are working so hard to remove it.

    Also, have you checked the TA of your fill water?
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    Re: Decision Making Time. Drain it or not?

    To go a step further, I suggest to drain the 80% out and then fill at one end of the pool and continue to drain at the other end of the pool. You will need to match the fill rate to the drain rate and this will help drain more of the CYA water. Test the results and see if this is helping to remove the CYA.
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    Re: Decision Making Time. Drain it or not?

    Quote Originally Posted by ping
    To go a step further, I suggest to drain the 80% out and then fill at one end of the pool and continue to drain at the other end of the pool. You will need to match the fill rate to the drain rate and this will help drain more of the CYA water. Test the results and see if this is helping to remove the CYA.
    Unfortunately both drains are at the deep end of the pool. The only option I see is continue to add water in the deep end with the drains opened and keep testing that 20% volume of water to monitor cya.

    Quote Originally Posted by ohm-boy
    Also, have you checked the TA of your fill water?
    Yes, and I know it is quite high. And the pH is quite low just like my pool likes to be oddly enough. Regardless, I believe I will do another drain in the near future, I just ran out of cya reagent and have some on order, so I will wait to drain until my order arrives and I can test the deep end water before refilling.

    Here are my new test results, as expected the cya is off the charts like it has always been any time I have used this test kit.

    FC 48
    CC 0
    TC 48
    pH 7.5
    TA 230
    CYA 100 + (Doesn't make it anywhere near the first gradation mark (100) on the TF100 test vial. I have never had a test make it up to the first mark in 3 yrs, even with repeated partial pool drains.)

    At this point I am happy the pH is at least normal because I observed some symptoms of rusting in my DE filter when opening, it had some rust on the wingnuts which i replaced and also on the metal o-ring support band. I cleaned as best as I could.

    I don't plan to spend anymore money on adding anything until I can do the partial drain, and test the cya.
    10,000 gallon
    Viking Freeform Fiberglass Inground Pool. FNS Plus DE Filter Pentair Challenger .75hp pump

    NC KANSAS44

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    Ohm_Boy's Avatar
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    Re: Decision Making Time. Drain it or not?

    I don't plan to spend anymore money on adding anything until I can do the partial drain, and test the cya.
    I agree. Again, I simply cannot fathom how high your CYA must have been initially. Drain/fill dilution will lower the CYA in proportion to the amount of water replaced, so you ARE lowering the CYA when you do this.

    I am also happy to see the ph at a reasonable level.
    [center:1kpalu48]Helpful Links: Pool School | CYA/Chlorine Chart | Pool Calculator[/center:1kpalu48]

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    Re: Decision Making Time. Drain it or not?

    Wow, that would have to be an incredible amount of initial CYA.
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    Richard320's Avatar
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    Re: Decision Making Time. Drain it or not?

    1)Yes, drain.
    2)Stop using stabilized chlorine.

    You might try getting a large plastic tarp. LARGE. Lay it on the pool and start filling above it while pumping out the drain. At some point you will have a bag of fresh water in your pool. Then push one edge in so the bag starts emptying and pull it out the other side. The pool was never empty, so it won't pop out, but the two waters don't mingle until you want them to.
    16K freeform gunite with spa; Pentair 4000 DE filter; Century Whisperflow 1 HP; Pentair Minimax heater.
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