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Thread: Powder/dust in pool

  1. Back To Top    #1

    Join Date
    Dec 2015
    Location
    Silver Spring, Maryland
    Posts
    30

    Powder/dust in pool

    In October, I took over a pool that was maintained for years by the same pool guy. I only had it for three weeks and did not have the time to wrap my head around the chemistry. I studied up all winter long and I now have a much greater understanding of pool chemistry thanks to this site and its members. We just opened the pool about 10 days ago, and it went pretty smoothly other than a faint green ring around the water line that easily rinsed off, and about a thousand dead worms on the bottom of the pool. I ran the cleaner a few times and subsequently tested the water. These were my results:

    FC .6
    CC .2
    TA 110
    PH 8.0+ (pool company later tested and said 8.7)
    CH 160
    CYA 300+ (diluted 3:1 tap/pool water, still was off scale)
    temp: 46 degrees

    I used 1 121oz jug of 8.25% bleach and a 1lb. package of 53% cal-hypo to raise the FC (not at the same time though), and I used dry acid to lower ph. I'm getting muriatic acid soon.

    I'm currently doing a simultaneous drain/fill to reduce the CYA, and relying on test strips to gauge CYA levels as to not waste too much reagent during this process. I can only imagine what the CYA level was at closing because I had to drain out tons of snow melt and rainwater-at least 6,000 gallons-and I've replaced another 6,000-9,000 gallons since opening. (PS- I do have a SWG, but I am manually chlorinating the pool with liquid bleach until I can get the CYA level down)

    These were my results a few days later

    FC 9
    CC 0
    TA 90
    PH 7.6
    CH 220
    CYA ~150
    Temp: 55 degrees

    The water is crystal clear now, however I noticed that there is a ton of what I suspect to be calcium scaling that I don't remember being there before, although I may not have noticed it. Also, every time I clean the robot, I notice a grayish "sludge" that dries into a very fine white powder. This powder ends up everywhere-if water splashes out and it is allowed to dry, there will be a very pronounced white spot there. When I brush the pool, the water becomes very cloudy and takes an entire day to clear up. A significant amount of this cloudiness occurs when I brush the plaster below the tile line, but above the 'winterized' water line I maintained. My guess is this powder is calcium, but I'm not certain.

    My questions are:

    1. Is this calcium, and if it is, does it filter out? (I have a DE filter)
    2. If the particles are too small to be filtered, how do I remove it from the pool?
    3. If it is calcium, will the suspended particles cause problems with my heater? I'm worried that it will cause scale inside the heat exchanger, due to the temp rise.
    4. I'm pretty sure the ph was around 7.6 at closing, but what would make the ph rise so much over the winter months? We got so much snow and rain this year, isn't that acidic?

    Thanks!
    ~24k gallon 38x22 figure-8 freeform pool w/ spa. Pentair EasyTouch 8SC w/ ScreenLogic2, intelliflo VS 011018 3HP, Intellichlor IC60, FNS Plus 60 DE filter w/ multiport valve, Raypak R406A cupronickel (360k BTU). ColorSplash 2G LED, Dolphin Nautilus Plus, Polaris 280 with 3/4HP booster pump.

  2. Back To Top    #2
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: Powder/dust in pool

    The dust may well be Calcium. The good news is, if it's big enough to see, the filter can catch it.

    Since you need to drain about 50% still, yours is one of the very few cases where I'd recommend trying a flocculent. It will bind any floating dust into particles that will settle out and then you can vacuum them away. Hopefully you have a multiport valve on your filter so you can vacuum to waste to get rid of whatever it is and lower the CYA at the same time. You'll need to brush vigorously to get the dust stirred up so the floc can bind it. You'd have to brush anyway for the filter to get it, anyway. Take Motrin pre-emptively.
    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!

  3. Back To Top    #3

    Join Date
    Mar 2016
    Location
    Marietta
    Posts
    44

    Re: Powder/dust in pool

    Mine did something similar..It would get very cloudy and if I added that drop and flock stuff would get clear but have a fine dirt on the bottom. After battling it ( before I knew about this site ) I drained and pressure washed the pool and refilled..It looked like sand but was super fine..Strange because I had a cartridge filter at the time. I also had dead worms but we had a very rainy year in Georgia and I read they climb to the pool deck during heavy rains and fall or get washed in.

  4. Back To Top    #4

    Join Date
    Dec 2015
    Location
    Silver Spring, Maryland
    Posts
    30

    Re: Powder/dust in pool

    Sorry for the late reply but thanks for the responses! I cranked the heat up to 84 degrees and went swimming with goggles yesterday so I could inspect the plaster up close. Since these irregularities don't show up in photos taken from above the surface, I'll try and take some photos underwater later. I really can't tell if the plaster is eroding or if something was deposited on the surface. Some parts have what I consider to be a normal plaster- not too smooth, not too rough- some brighter white spots are so smooth they feel slippery, almost slimy, and areas between the tile line and the winterized water line seem a bit rough. I know my CH is low, and my fill water also has pretty low CH (the TDS of my fill water is only 100). I'm not sure what it has been at historically since I've only been able to test the water with a kit as of a few weeks ago.

    Yesterdays test-

    FC- 6.2
    CC- .2
    PH- 7.2, upped to 7.4 (I think the 600lbs of salt I added lowered the ph drastically)
    TA- 90
    CH- 180
    CYA- 80
    Salt- 3200
    Temp 84 degrees

    I realize my CSI is negative, but it was positive at opening due to ridiculously high ph.
    ~24k gallon 38x22 figure-8 freeform pool w/ spa. Pentair EasyTouch 8SC w/ ScreenLogic2, intelliflo VS 011018 3HP, Intellichlor IC60, FNS Plus 60 DE filter w/ multiport valve, Raypak R406A cupronickel (360k BTU). ColorSplash 2G LED, Dolphin Nautilus Plus, Polaris 280 with 3/4HP booster pump.

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