Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 4 of 4

Thread: Sand to DE filter help

  1. Back To Top    #1
    jcowart's Avatar
    Join Date
    Jun 2012
    Location
    Labelle, TX
    Posts
    320

    Sand to DE filter help

    Just want to say I love this forum. I have an 18k AGP. One skimmer and one return...so no water features. Right now I have a powerline "DB" 1.5hp with a Aquaview 20" sand filter. The pad is right their and is plumbed with 1.5" PVC. Total of 8' from skimmer to return. The water is very clear in the day but skim milk at night with the light on. My OCD has convinced me that it could be better. I keep my water balanced and had no problems last year other than at night with the light on. I learned that my pool uses about 1.5 ppm a day in the hot southeast Texas sun, and could even judge it by the cloud cover. Right now my levels are:
    FC 6
    CC 0
    Ph 7.5
    TA 90
    CYA 50
    CH 180
    I took my filter apart and pulled out cotton like stuff and washed the sand with a hose. After I started it back up and let it settle I added some DE. The problem is as soon as I started to add it I could see a white haze from the return. I found a DE filter for sale for $350. It's a Hayward EC50C92S 1hp with 3 way valve. The specs show it as 25 sq ft with a flow of 50gpm. What I come up with is 18000gal/8hours/60mins is 37.5gpm. Is the average DE 2gpm per sq ft? If that's right then I would need a min of 18.75 or say 20 sq ft.
    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"

  2. Back To Top    #2
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Sand to DE filter help

    For an 18k gallon pool, we would generally recommend a 3.2 sqft (24") sand filter or a 48 sqft DE filter at a minimum.

    So, your current filter is slightly small and your pump is pretty oversized ... a common problem we see. That DE filter is much too small. Our filter recommendations are based on pool size and the pump size is based on water flow needs ... you do not seem to have high flow rate needs, so the smaller the pump the better. Rarely is the filter recommendation too small for the pump recommendation.

    It sounds like something may be off in your current filter. It may be worth a thorough inspection to see if anything is cracked/displaced and allowing the debris through the sand.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

  3. Back To Top    #3
    jcowart's Avatar
    Join Date
    Jun 2012
    Location
    Labelle, TX
    Posts
    320

    Re: Sand to DE filter help

    I have searched and searched. Where or how do you come up with 48 sq ft. I figured the filter and pump was not sized right but that's what I have to work with. I did notice that the sand was lower on the right side "away from the pump". Once washed, it was level all the way around and up to where the tank starts to round up. I just pulled the valve again and the sand is lower on the right side again.
    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"

  4. Back To Top    #4
    Mod Squad jblizzle's Avatar
    Join Date
    May 2010
    Location
    Tucson, AZ
    Posts
    37,389

    Re: Sand to DE filter help

    There is a table here: hydraulics-101-have-you-lost-your-head-t915.html#p6543 for filter sizing. We generally recommend the table value for sand and double the table value for cartridge and DE to reduce the frequency of filter cleaning.

    Really you can go as large as you want for a cartridge filter, but for sand and DE you have to be sure you have enough pump power to adequately backwash.
    Jason, TFP Moderator
    18k IG pebblesheen pool, Hayward ProLogic P4 w/ T-15 SWG, Pentair 1HP 2-speed Superflo, Hayward 6020 DE filter
    500 sqft Heliocol solar panels, ThePoolCleaner, TF-100 test kit w/ SpeedStir
    Pool School + Test Kit + PoolMath = A TROUBLE FREE POOL
    If you found TFP helpful and we saved you money ... Become a TFP Supporter!

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •