Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 7 of 7

Thread: When to backwash?

  1. Back To Top    #1

    When to backwash?

    At what PSI do I need to backwash? And for how long do I run it? And should I rinse after the BW?

    I guess that turned into 3 questions
    27' round AG, sand, Ohio, well water, 19,000 gallons approx., New owners to the pool.

  2. Back To Top    #2
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    8,618

    Re: When to backwash?

    Backwash when your filter pressure raises 5 or 6psi from the clean pressure. If you have a sight glass, backwash until the water runs clear. If not, at least a minute, maybe 3 or 4 depending on how dirty the water is. I backwash for 3 or 4 minutes whenever we have a heavy rain just to take advantage of the free water to thoroughly clean the sand.

    Always rinse after backwashing.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  3. Back To Top    #3

    Join Date
    Mar 2007
    Location
    Coastalish 'down easter'
    Posts
    4,160

    Re: When to backwash?

    I like that idea John If Ma Nature gives you the water, why not backwash instead of 'wasting' it
    Luv& Luk
    -Ted

    Having done construction and service for 4 pool companies in 4 states starting in 1988, what I know about pools could fill a couple of books - what I don't know could fill a couple of libraries :-D

    POOL SCHOOL, TF Testkits, Jason's Pool Calculator, CYA vs. cl chart, (Just a few DARNED handy links!)

  4. Back To Top    #4
    Mod Squad JohnT's Avatar
    Join Date
    Apr 2007
    Location
    SW Indiana
    Posts
    8,618

    Re: When to backwash?

    Quote Originally Posted by waste
    I like that idea John If Ma Nature gives you the water, why not backwash instead of 'wasting' it
    With the TA of my fill water being between 450 and 500ppm, I don't backwash unless I have to if I'm going to have to replace it from the hose.
    TFP Moderator
    20K Gallon 20X36 Vinyl Inground
    Hayward S244T Sand Filter with 1HP Whisperflo Pump. Liquidator C-201 and Solar Heat

  5. Back To Top    #5

    Join Date
    May 2009
    Location
    West Tennessee
    Posts
    33

    Re: When to backwash?

    I think there is an article in pool school on this and the way I understand it (I 've been doing it wrong all these years) is to backwash for a minute or so the rinse for 20 - 30 seconds then go back thru the backwash cycle again and rinse until your water is clear from the backwash. This could take ten minutes or longer depending on how dirty your filter is. Most manufacturers recommend backwashing when your filter when the pressure raises about 8 psi above the clean filter pressure.
    18,500 Gal. 27 ft AG Vinyl - Hayward Pump with Cooper 21" Sand Filter - GO VOLS!

  6. Back To Top    #6
    NWMNMom's Avatar
    Join Date
    Apr 2007
    Location
    Waaay NW MN
    Posts
    1,582

    Re: When to backwash?

    Only backwash when you have to and take steps to avoid putting organic materials into a filter that lead to the requirement for backwashing. Each time you backwash, you lose some of your sand. Is it a lot? Probably not but over time, it adds up. I have spoken with people who made it a habit to BW twice a day and then wondered why the sand needed to be replaced so soon. Use a skimmer sock, a leaf rake or vacuume with a leaf canister inline, etc to avoid getting more stuff in there than you have to. Our PR Jr does a nice job of removing a lot of the gunk that would end up in my filter.

    BTW, I do follow the Mother Nature rule above about using that free water to do a BW if needed. Seems like there isn't ever a shortage of rain events that leave us with too much water.
    18x33x52 Buttressfree Seaspray (Wilbar) AGP - 1.5hp Pentair Maxim w/22" Pentair Meteor Sand Filter, Aqua Rite SWG System, Biltmore Walk In Steps - 2/4x20 Solar Panel Setup - Doheny Jet Drive (RIP -Pool Rover Jr) - finally hard plumbed the whole darned thing -
    Beats Driving to the Lake!

  7. Back To Top    #7
    AnnaK's Avatar
    Join Date
    Jul 2007
    Location
    Eastern Pennsylvania
    Posts
    1,132

    Re: When to backwash?

    IMO, heavy rains are a gift to pool owners for the free backwash water they provide.

    Yes, rinsing is a required part of backwashing. The backwash cycle forces water through the sand in the opposite direction from the filter flow. It stirs it up to dislodge the debris. The rinse cycle packs the sand back down.

    I use a white plastic pitcher to catch some of the backwash water. When there's no more debris in it, no little floaters, I change to rinse. ALWAYS turn off your pump when changing a setting! I rinse for 30 seconds. If I have a lot of water available I run a second backwash/rinse cycle.
    — AnnaK —

    12,000 gal AGP, Hayward sand filter, Pentair 2-speed pump, timer.
    Please visit our Pool Issues pages for information about step weights, managing the solar cover, and PoolSkim.

Posting Permissions

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