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Thread: Dirt looking stuff on bottom of pool

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    Dirt looking stuff on bottom of pool

    Pool water looks good, but I have some sort of black stuff on the bottom and it appears to be spreading. I've brushed it several times but it doesn't change/move at all. I've brought the pool up to shock levels, but didn't maintain them there as I didn't have time to do overnight FC loss. The CC's go to 0 though. Should I go back and repeat the shock treatment? Anything else look to be a problem from the pictures?

    Thanks for any help,

    Jim

    FC=3.0
    CC=0.5
    TC=3.5
    CYA=20
    CH=230
    TA=90
    pH=7.5




    Pool water looks clean:

    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    duraleigh's Avatar
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    Re: Dirt looking stuff on bottom of pool

    Can't tell what it is from the pics....was it there last year? Have you had good luck with keeping your water very clear each summer? Any prolonged algae outbreaks?
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Dirt looking stuff on bottom of pool

    It wasn't there last year and this is my first year with the pool. Last year starting in August when I took over the pool I didn't have any problems. I do know lots of stuff from the trees was dumped into the pool and it has been a battle just keeping all the leaves and debris out.

    Also, I went out and checked the supplies that the previous owner left and I found some polyquat. So there is a possibility that they were having this problem too.
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    Monday I cleaned the filter, vacuumed, and then brushed the pool. Tuesday evening I shocked the pool by putting 242 oz of 8.3% bleach in the pool. After a few hours I measured the FC and it was at 14 (still trying to figure out how many gallons are in the pool, was told 25k/28 but I think it is less). I also hung a sock with stabilizer in it by one of jets using the pool calculator and specifying that the pool was 17k gal so that I knew I wouldn't over do it.

    I took a chlorine tablet and rubbed in on some of the spotted areas and it didn't seem to have any effect. I also tried to scrape some up but couldn't get any to come off. It is hard to get to because the pool has a ruff concrete surface. I set a tablet on it for over an hour and there was no difference.

    This morning I measured the FC and it was at 11.5. I brushed the pool again and there is no noticeable difference in the black spots (they may be worse). I did notice that there is a spot that looks like it was left behind from a paper clip, I believe there was one in there when I opened the pool this year. Probably dropped by one of the pool guys I had working on it last year.

    I believe I should complete the shock process and maybe try some vitamin C on some of the spots. Is this worth doing or am I just being a little impatient?
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    Just looked at the chems that I had the pool store do last year when I bought my house/pool and they showed copper and iron in the pool.

    their readings were:
    Copper 1.22 ppm
    Iron 0.06 ppm

    Also, I noticed when I did the CH test that the sample turned purple before it made it to blue, took a couple of more drops to get it to blue.
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    Is there anything else I should do other than continuing the shock?
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    Finished the shocking. This morning I check the FC and CC. FC was the same as it was last night and the CC's were Zero.

    Am I done? I still have the black spots and the water is crystal clear.

    Please advise.
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    Have you touched the black stuff? Is it greasy? Can it be vacuumed up? If so, I had solar panels on the roof that started "shedding" on the inside and your picture looks like what I had on the bottom.

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    Re: Dirt looking stuff on bottom of pool

    It seems that all the black stuff is in the crevasses in the concrete. I have tried to touch it, scratch it, rub it, scrub it...nothing working. I put vitamin C on it and I have but Chlorine tablets on the and they don't change.

    There is a heater hooked to the system that doesn't work...

    I got nothing and no idea on what to do
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    Still trying to get something to remove the black spots in my pool. I have kept the CL from 7 - 10 ppm for over a week now after shocking it the previous week. The spots haven't faded at all.

    The black spots are contained in the shallower areas of the pool. The only ones that I can see in the deep end are in the swim-out.

    Any ideas on what I should try next?
    ____________________________________________________________ _____
    IG 25,000 gallon concrete painted pool,
    KDI American Products Model# 583090 Titan SS Vertical Grid 48sq ft DE filter

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    Re: Dirt looking stuff on bottom of pool

    A painted pool surface may be impossible to remove all the stains. If high FC didn't budge it, I am at a loss..
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Dirt looking stuff on bottom of pool

    Trichlor granular in the crevices. That's probably your last hope for those other than painstakingly taking a small tool to scrape them out, but being underwater you'd need scuba gear!
    16,000 gallon outdoor in-ground 16'x32' plaster pool; Pentair Intelliflo VF pump; Pentair IntelliTouch i9+3s control system; Jandy CL-340 square foot cartridge filter
    12 Fafco solar panels; Purex Triton PowerMax 250 natural gas heater (200,000 BTU/hr output); automatic electric pool safety cover; 4-wheel pressure-side "The Pool Cleaner"

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