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Operating Your Sand Filter

Here are a few tips to remember before you get started operating your sand filter system.
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The oldest and most popular method of filtration is sand. Sand filters use a special filter sand, normally .45 to .55 mm (also known as pool-grade #20 silica sand), because it has sharp edges that serve to separate particles, allowing filtration to take place. Sand filters are the least expensive of the three types of filters but only filters particles down to 20 to 40 microns in size. Operating your sand filter would require some knowledge but still one of the easiest ways to keep your pool clean.

Here are a few tips to remember before you get started Operating Your Sand Filter:

  1. Always shut filter off before moving valve handle. (Valve handle will be seriously damaged if you do not.)
  2. Always backwash the filter immediately after adding new sand to the filter.

Operating your sand filter

Starting the Filter System

Before plugging in filter, turn valve handle (located on top of filter) to the backwash setting. Water will begin to flow out of the backwash port plug in filter briefly until water begins to run clear. (if you need to send backwash water a longer distance, backwash hoses are available in 25, 50, 100 & 200ft lengths). Unplug filter, turn valve handle to filter position and plug in filter. You are now filtering your pool water.

Pressure reading on pressure gauge, will be between 6-12 psi. This initial pressure will be your normal operating pressure. When water return flow becomes weak or there is a surge in the pressure gauge reading it is time to backwash.

What is Backwashing?

Backwashing completely clears filter of all dirt & debris by reversing the flow of water through the filter. To backwash, simply unplug filter and move valve handle to the backwash position. Then plug in filter and let water run until clear. When water runs clear unplug filter, move valve handle back to the filter setting, and you are ready to filter again.

How long should filter run each day?

Most Sand Filters turn over approximately 2400 gallons per hour. It is recommended that you turn over the water in your pool at least twice a day (refer to chart at bottom of page for your pools capacity). Run filter more in hot weather or with heavy bather load. As a general rule of thumb, turn your sand filter on 1 hour per 10° F of weather.

Pool Capacity Cheatsheet

Pool SizeCapacity (Gal.)Pool SizeCapacity (Gal.)
10 Round2,0008x12/14 Oval2,500
12 Round3,0008x15/16 Oval3,000
15 Round5,0008x19 Oval3,500
18 Round7,50010x15/16 Oval3,500
21 Round10,00010x18/19 Oval4,000
24 Round13,00010x21 Oval5,000
27 Round17,00012x16 Oval4,500
30 Round21,00012x17/18 Oval5,000
33 Round25,00012x20/21 Oval6,500
12x24 Oval7,500
14x20 Oval7,500
15x23/24 Oval10,000
15x30 Oval12,500
16x26 Oval12,500
16x32 Oval15,000
18x33 Oval17,000
18x40 Oval18,000
21x43 Oval24,000
Please note: Pool calculations below have been rounded off to be used as a quick guide for easy pool maintenance. For exact calculations please use our pool volume calculator.
AquaPro 19" Sand Filter System 2-HP Pump 2 Year Warranty

The AquaPro 19″ master series is a high-rate sand filter that offers leading edge technology for unparalleled efficiency, flow and serviceability. The 7-way valve provides simple operation and dependability. The compact design, along with maximum filtering capability, reduces maintenance and time.

  • May 4, 2013 at 6:11 PM
    Julianne Bowers

    We just bought a house with a sand filter pool, and are turning it on for the first time. When it is on “filter” setting, water is coming out of the blue hose that I assume is the backwash. Does that mean the filter is broken?

    • May 22, 2013 at 8:11 PM

      The backwash valve may need replacement or most likely the filter hoses were hooked up incorrectly.

  • May 31, 2014 at 2:53 PM

    The pressure gauge on my Hayward sand filter fills water as I use my filter, what can be the cause?

  • June 24, 2014 at 7:18 PM

    My pool has been cloudy since installing a sand filter. I followed instructions and have new sand. What do I need to do?

    • June 25, 2014 at 11:32 AM

      This is a common problem when installing new sand but not completely cleaning the sand before use. New filter sand has a lot of fine sediment that can cause cloudy water. If the sediment has settled on the bottom of the pool we would recommend vacuuming on the waste setting to remove it from the pool.

      If you can’t see the bottom of the pool because of the cloudy water we would recommend the following:

      1. Balance the PH and the Alkaline levels.
      2. Raise the chlorine level to 5ppm.
      3. Run the filter continuously for at least 72 hours or until the pool clears.

  • August 8, 2014 at 4:23 PM
    Richard Hamilton

    I just installed a pool and new sand filter. I back washed the system, then rinsed, then put on filer. The back wash outlet starts out as a slow drip of water coming out of it the longer the pump is on the more comes out until it is coming out like the end of a water hold nozzle. Any idea why this happens and how can I fix it.

    • August 8, 2014 at 4:46 PM

      Hi Richard,

      You may have the hoses hooked up incorrectly. If you look carefully at the top multi-port valve you will see the words “pump”, “return” and “waste”. The heavy black hose gets connected to the top of the pump to the port on the valve that says “pump”. The hose from the bottom of the thru-wall skimmer connects to the front of the pump. The hose from the return jet of the pool connects to port on the valve that says “return”.

  • June 14, 2016 at 10:08 AM
    Rabbi Y. G

    I have a Hayward sand filter from your firm. The moter does not start just makes a humming noise and then the fuse goes. I called a electrician and he changed the plug but the problem was not solved. This filter is for a religious ritulamium in a synagogue. Can you help. Thank you in advance.

  • June 23, 2016 at 11:40 PM

    Bought new pentair 19 sand filter when I run it on filter it didn’t reseculate the water out of the return house the house is full of water when I back wash the water is hot

  • July 6, 2016 at 5:42 PM
    Anna Flores

    Please explain waste setting.

    • August 17, 2016 at 3:40 PM

      Hi Anna,

      The waste position pumps the water out of pool, the water will bypass the filter and just go directly out of the waste port of the multi-port valve.

  • August 11, 2016 at 3:18 PM
    Mary Nadolney

    Is a sand filter all I need for my pool. I don’t really understand what it is. Does it take the place of my old filter system where I have to replace the white paper kinda filter a couple times a week or is this sand filter all I need? Please tell me I can throw the other one in the garbage. Lol. Ty mary

  • August 12, 2016 at 9:28 PM
    N. Mondi


  • May 2, 2017 at 4:51 PM
    Precious Leyva

    I didn’t know what backwashing was or the importance of it. My husband and I have considered putting in a pool and we’ve been investigating filter systems. I’m a bit of a clean freak so having a clean filter is important to me. Backwashing seems like that is an important step in maintaining your pool filter.

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