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Thread: Little bit of sand when backwashing?

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    Little bit of sand when backwashing?

    I notice a little bit of sand swirling in sight glass and in driveway where water comes out of hose when backwashing. Is this normal or should I be looking for a problem? Thanks.
    16x28 Roman, 55000 litres, salt water, Zodiac Duoclear 130 (mineral cartridge removed!!!), inground, vinyl liner
    Hayward Tri-star VS900 (1.85 HP) pump, Hayward C3030 cartridge filter
    Nine Techno Solis 4x10 solar panels, Jandy LX 250 natural gas heater
    Jandy Aqualink PDA with Sub Panel Power Centre

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    linen's Avatar
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    Re: Little bit of sand when backwashing?

    How much are we talking about? If it is just a little, then it is probably not a problem...I some times loose just a little sand during backwash due to the stupid cotton tree fluff that whips up a little sand enough to flush out. Are you getting any sand in the pool on filter?
    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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    Re: Little bit of sand when backwashing?

    Thanks for answering. No sand in the pool. Not a huge amount on backwash either - I can see it swirling in the sight glass, and it shows up clearly on the black driveway where the backwash hose ends but it is a small amount. I just can't remember if it always did this or not. What would be the likely cause if there was a lot of sand washing out?
    16x28 Roman, 55000 litres, salt water, Zodiac Duoclear 130 (mineral cartridge removed!!!), inground, vinyl liner
    Hayward Tri-star VS900 (1.85 HP) pump, Hayward C3030 cartridge filter
    Nine Techno Solis 4x10 solar panels, Jandy LX 250 natural gas heater
    Jandy Aqualink PDA with Sub Panel Power Centre

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    Qwaxalot's Avatar
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    Re: Little bit of sand when backwashing?

    As long as you're not seeing any sand in the pool, the laterals are probably fine. A little sand in the backwash is generally caused by a little too much sand in the filter, a self correcting problem.

    Just be sure to rinse thoroughly after backwashing!
    In the industry, CSP (Certified Service Professional) by the NSPI and it's successor the APSP. My company services over 600 pools every year. I think the practices regularly espoused on this forum (especially the BBB method) are outstanding; however my comments will be often oriented towards the goal of getting it done, and getting it done right now!

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    Re: Little bit of sand when backwashing?

    Ok...update. Now I'm getting sand in the pool. Not a huge amount, but over several days I can see it on the bottom. Is this likely a lateral problem, or could the multiport valve be involved. Remember, I'm seeing sand in the backwash water too.

    Thanks.
    16x28 Roman, 55000 litres, salt water, Zodiac Duoclear 130 (mineral cartridge removed!!!), inground, vinyl liner
    Hayward Tri-star VS900 (1.85 HP) pump, Hayward C3030 cartridge filter
    Nine Techno Solis 4x10 solar panels, Jandy LX 250 natural gas heater
    Jandy Aqualink PDA with Sub Panel Power Centre

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    Re: Little bit of sand when backwashing?

    Make sure it is sand in the bottom of the pool. Many folks on the forum are mistaking dead algae for sand.
    Dave S.
    42k vinyl and concrete pool, 1.5hp pump, 140gpm filter
    TFTestkits , PoolMath , Pool School

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    Re: Little bit of sand when backwashing?

    Thanks. Next time I see it I'll swim down with a dive mask on and have a closer look, instead of just vacuuming it up.

    I did just finish a couple of hours of removing the sand (thank you, Shop VAC) and checking the laterals and they all looked good. I have two labs, and the amount of dog hair in the sand that hasn't been coming out when backwashing was incredible. Luckily, it was all clumped up and easy to remove. A lot of the sand seemed very compressed as well, and it's now all loosened up.

    After putting the sand back in, I backwashed and the water in the sight glass was really dirty. Same with the rinse. I guess 5 years of crud embedded in the sand wasn't being removed in a normal backwash - not until I loosened all the sand did it wash out.

    Anyhow, I'll check what I think is sand to make sure it's not dead algae the next time I see it.
    16x28 Roman, 55000 litres, salt water, Zodiac Duoclear 130 (mineral cartridge removed!!!), inground, vinyl liner
    Hayward Tri-star VS900 (1.85 HP) pump, Hayward C3030 cartridge filter
    Nine Techno Solis 4x10 solar panels, Jandy LX 250 natural gas heater
    Jandy Aqualink PDA with Sub Panel Power Centre

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