Become a TFP Supporter Pool Math Forum Rules Pool School
Results 1 to 8 of 8

Thread: when to backwash

  1. Back To Top    #1

    when to backwash

    when should i backwash my filter and how often and what process its got backwash rinse on multi port and how long do i back wash and rinse
    16\32 30,000 gallon inground pool triton II sand filter 3 h.p pump hayward chrlorinator

  2. Back To Top    #2
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: when to backwash

    You should have a pressure gauge on the filter, when it goes up about 10 PSI from its base pressure from when it was freshly backwashed it is time to backwash again.

    Ike

    p.s. the typical pool pressure gauges are cheaply built if yours does not move either before / after backwashing it may be sticking
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

  3. Back To Top    #3

    Re: when to backwash

    its been staying at 8 psi for 4 days now it will go down when i cut pump off
    16\32 30,000 gallon inground pool triton II sand filter 3 h.p pump hayward chrlorinator

  4. Back To Top    #4
    Isaac-1's Avatar
    Join Date
    May 2010
    Location
    SW Louisiana
    Posts
    6,711

    Re: when to backwash

    You need to determine a baseline for pressure when it is freshly backwashed, whatever that pressure is backwash when it goes up about 10 psi.

    Ike
    Indoor 20x40 35,000 gallon vinyl pool with 1.5 HP 2 speed Jandy FloPro pump, Hayward EC75 Perflex DE filter, 11 4x12 Techno-Solis solar panels w/ Aquasolar controller, Aquabot Turbo T Robot Cleaner. Also LMI metering chlorine dispenser pump and HotSpring Jetsetter
    I use and endorse TFtestKits TF-100 from http://tftestkits.net
    ~Remember TFP counts on your donations to keep this site ad free~

  5. Back To Top    #5
    Voodoo_Pool's Avatar
    Join Date
    May 2011
    Location
    On the border AR/TN
    Posts
    82

    Re: when to backwash

    From Pool School: While most people know that a filter is a key component of a swimming pool's filtration system, quite a few do not realize that the filter needs to be cleaned periodically to insure proper equipment performance and cleanliness of the pool water. This article will discuss why maintenance cleaning is a good idea, then tell how to clean each of the 3 types of filters; cartridge (or cart), sand and finally both types of the Diatomaceous Earth (DE) filters.

    When your filter was new the water could easily pass through it - the pounds of pressure per square inch (psi) shown on the filter's pressure gauge probably read ~8 - 20, depending on your pool and plumbing set up. As the filter does its job and filters, the debris in the water gets removed, there is less room for more new debris and the pressure rises. When the pressure rises too much (usually 8 - 10 psi) it's time to clean out the stuff that has already been captured in the filter so you have room to catch any new debris that enters the pool. Failure to keep the pressure in the normal range can result in cloudy water, poor circulation and excessive wear on the pool equipment.

    Sand filters make use of a multiple position valve (multiport or multi) for cleaning the debris trapped by the sand. Whenever changing the position on a multi, you MUST have the pump off or you will break something. First make sure that any valve on the discharge line is open and any discharge hose is rolled out to where you want the dirty water to go. After turning off the pump, move the lever to the "BACKWASH" position and restart the pump. Most multis have a view glass so that you can see the debris coming out of the filter - when the water in the glass is ~ clear, turn off the pump and switch the multi to "RINSE" and run the pump for ~ 15 seconds. Repeat the "backwash/ rinse" cycles until the water comes out clear when you do the final backwash. Then reposition the valve back to the normal "FILTER" position, and you're all set until the unit needs to be cleaned again. Please note that this process removes water from the pool, so be sure to keep an eye on the water level and don't start the cleaning process if the water is already low! Some multis have the "BACKWASH" function, but not the "RINSE', this is also true of multis with a pull up - push down handle - in either of these cases, a 10 second "FILTER" cycle can be used instead of the "RINSE".
    22,000 gallons "L" shaped with spillway spa; Hayward 4820 DE; IG Vinyl; 2000 ppm salt; 50 ppm Borates; liquid chlorine; Polaris w/ booster; TF-100 Test Kit w/SpeedStir

  6. Back To Top    #6
    JasonLion's Avatar
    Join Date
    May 2007
    Location
    Silver Spring, MD
    Posts
    37,879

    Re: when to backwash

    Quote Originally Posted by Voodoo_Pool
    Sand filters make use of a multiple position valve
    Usually true, but not always. Sometimes they have a much simpler push/pull two position valve.
    19K gal, vinyl, 1/2 HP WhisperFlo pump, 200 sqft cartridge filter, AutoPilot Digital SWG, Dolphin Dynamic cleaning robot
    Creator of PoolMath and Pool Calculator. Other handy links: Support this site, TF Test Kits, Pool School

  7. Back To Top    #7

    Re: when to backwash

    I have a variable speed pump. My new 60 sf filter (and new gauge) only measures about 1 psi when it is running. If priming (higher GPM) or if I adjust my run-time to a much shorter period (forcing a higher GPM), the pressure will increase with the higher water flow. I like to run my pump for a longer period of the day to keep sweeping leaves off so I have the very low PSI while running the pump.
    My long-winded background gets me to my question: If I get less than 1 psi when clean and new, do I still use the +10 psi as my backwash/cleaning guide?
    20x40 vinyl liner -- 30k gallons
    Pentair Intelliflo pump
    Pentair FNS Plus Polypropylene DE Filter - 60 SF
    Aqua Rite Electronic Chlorine Generator
    TF 100 test kit

  8. Back To Top    #8
    Richard320's Avatar
    Join Date
    Jan 2010
    Location
    San Dimas, CA (LA County)
    Posts
    18,768

    Re: when to backwash

    I believe the 10 psi rule dates back to single-speed pump days. I'd say when you gain 10 psi on high speed, it's time to backwash.

    You can reduce a lot of that by stretching a knee-high nylon over your skimmer basket. I catch piles of stuff, looks like the dryer screen sometimes, in a nylon. I just carry it over to the trash can, flip it upside down and sort of brush it all off with my fingers. About every third time, the nylon shreds, so I replace it. There are also commercial skimmer socks for sale at the pool store.
    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!

Posting Permissions

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