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Thread: Used DE from backwash discharging in yard - Dangerous?

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    Used DE from backwash discharging in yard - Dangerous?

    So I've been a pool owner for 2 years, but something just dawned on me. My house is on septic and when I backwash my pool the outlet is literally about 4 foot away from the pump/filter and just discharges into the grass. I've never really liked this, but doesn't seem to cause any major issues with the grass. However, I just realized that the used DE is also coming out with that water and sitting in the grass. When I mow (assuming the ground is dry) won't some DE be thrown up in the air creating a fairly dangerous situation of me breathing in the used DE?? Does anything change in the makeup of the DE after its used in the pool or do I need to find a different solution to avoid getting lung cancer?!?

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    Re: Used DE from backwash discharging in yard - Dangerous?

    I'm not sure I'd go so far as to say you're in any kind of danger from mowing the lawn. I think the DE will get worked into the soil by the time you get the mower out. I am surprised however that it isn't killing your grass. It began to kill mine, which is why I went to a cartridge setup. During a backwash, the DE is well concentrated with the water, so again I wouldn't sweat the airborne issue. If though, when it comes time to pull the grids out and hose them off, I definitely wouldn't do it on the lawn. In that scenario, the DE would stay on the lawn surface for a much longer period, thereby increasing a possible airborne problem.
    26k Gunite freeform pool w/spa, Pentair CCP520, Pentair Mastertemp heater, Pentair 1HP 2-speed Superflo, Dolphin Oasis Z5


    Bob

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    chiefwej's Avatar
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    Re: Used DE from backwash discharging in yard - Dangerous?

    You could switch to cellulose fiber. It does cost a bit more than DE, but it cleans the water better, it's biodegradable, and it's not a carcinogen. It will beak down and will not hurt your lawn. I have made the change and I love how much better it filters.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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    Mod Squad tim5055's Avatar
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    Re: Used DE from backwash discharging in yard - Dangerous?

    X2 on the cellulose fiber. I use it with my sand filter with great results and no worries about where my backwash water goes.
    TFP Moderator 39 X 18 23,000(ish) freeform gunite; built 2007ish; Pentair Triton II TR100 600lb Sand filter; 2 HP Pentair pump with 2.2 HP AO Smith single speed motor; 2 skimmers, 1 main drain, 4 returns w/waterfall, Stenner 45MHP2 3GPD running@ 60% - 15 gal Tank; heated by the sun CYA 200+ when I started - 50 now. Dolphin Supreme M5 Pool Cleaner. Hot Springs SX Spa, 285 gallon

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    Pool Boy Hawk's Avatar
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    Re: Used DE from backwash discharging in yard - Dangerous?

    DE stands for diatomaceous earth and this means we're using fossils from prehistoric once living creatures called diatoms. The exoskeleton shells they make and leave behind are the filter material we use in our filters. These microscopic shells are primarily composed of silica, the stuff in sand but it's the biological version. diatomdiverse.jpg

    Breathing this stuff for extended periods of time can lead to a condition similar to asbestosis called silicosis. I drain my filter the same way you do and I also run over it with a lawnmower during the summer. I would say if you're concerned about it, take a flat shovel and skim it off the grass and topsoil while it is still damp and toss it in the trash. This will go a long way to minimize any potential risk.

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    jcowart's Avatar
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    Re: Used DE from backwash discharging in yard - Dangerous?

    I have the same problem. I have a perflex filter so I don't backwash with pressure like you. I bump the handle to knock the DE off the grids and gravity and water washes it out the bottom drain of the filter. What I did was I found an old sheer curtain. I cut a 3ft by 6ft section. I folded it in half and had my wife sew the sides up to make a "sack". I run my hose into the "sack" and bunch the open end around the hose and tie it with a piece of wire. The DE cakes on the inside of the sack. I let it dry a little and then dump it in a trash bag.
    17500 gallon Doughboy AGP, Hayward DE filter, waiting for the 1.5hp DB pump to go out.
    Learn to take the advice here and be trouble free or use the pool store's advice. "You can't do both and get very far"

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    Pool Boy Hawk's Avatar
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    Re: Used DE from backwash discharging in yard - Dangerous?

    That's a great idea. I'll have to try it.
    Hailing from the People's Republic of Maryland, the only state that taxes rain.
    27,000 gallon gun-nite in ground pool in Maryland, Nautilus NS 36 DE filter with Hayward 1.5 HP motor.

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    chiefwej's Avatar
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    Re: Used DE from backwash discharging in yard - Dangerous?

    There is also a thing called a separation tank. I have one installed on my system and it strains the DE out of the waste water.
    chiefwej
    Tucson, AZ
    16x36 rectangular (19k) Pebble Tec play pool/spa, Pentair Intelliflo VS 011018, Super II 2hp (spa), Aqua Rite T-15 SWG, Pro Grid 60 DE, Hayward H400 & Heliocol Solar heating, A&A infloor system, fill water w/high CH and TA, 50 ppm borates,TF-100 test kit

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