How To Backwash a Pool Sand Filter

WRITTEN BY: 

  3.59 out of 5 stars on 81 ratings
(Click on a star to add your rating)

After a period of time, the contaminates in a sand filter start to clog the sand to the point where water flow is significantly diminished and the pressure gauge rises 8 to 10 psi above normal operation readings. To clean out the contaminates, you have to backwash the sand. This guide shows you the steps in backwashing a filter.

Click Here to View Replacement Sand Filters

Click Here to View Replacement Parts for Sand Filters 

Video

Step by Step

Top

Step 1

Turn off power to your pool pump at the circuit breaker. To prevent damage to the valve, or any other pool equipment always turn off the pump before moving the multiport valve’s handle

Step 2

Depress the valve’s handle and turn it until the selector notch points to BACKWASH, then release the handle.

Tip for preventative maintenance: Always turn your valve’s handle the same direction when changing settings; either always right or left. Do not turn opposite direction even if the other way is a shortcut to your desired setting. This reduces chances of uniting the spider gasket and undue wear and tear.

Also, make sure the handle is fully depressed when turning the selector handle.

Step 3

Make sure Waste hose is securely connected to the valve, and free of kinks to allow for free flow to your desired drainage point.

Please Click Here to View the Backwash Hose

Please Click Here to View Hose Clamps

Step 4

Turn on the pool pump breaker, then turn on the pool pump. Let the pump run for about two minutes or until the water in the sight glass is free of silt. 

Note: If you’re planning a longer than normal backwash and rinse due to an excessively dirty filter, set you suction diverter to only pull water from your main drain. Making this change will prevent your pump from losing prime or running dry if the pool’s water level drops below the skimmer.

Step 5

Turn off the pump again

Step 6

Set the valve to Rinse. Depress the valve selector handle, then turn it to the Rinse setting. After a backwash, sand and debris becomes unsettled settle in the filter’s internal plumbing. The rinse setting returns to the normal path through the filter, flushing debris to waste.

Step 7

Turn the pump on, let it run for about a minute or until the sight glass is clear of silt and sand.

Step 8

Turn off power to pump to set the valve selector handle to its normal Filter setting.

Step 9

Turn on the pump to resume a normal filtering schedule. Check your pressure gauge to ensure the system’s pressure has returned to your pool’s normal “clean” PSI range.

Please Click Here to View Pressure Gauges.

If you experience issues after backwashing, here is a list of helpful how-to guides for troubleshooting:

How To Determine Why a Pool Pump Won't PrimeSand in Your Pool?

How to Reduce High Pressure in Your Pool System

How to Correct Low Water Pressure in Your Pool System

Comments

Top
(121 to 160 of 310)

 Posted: 6/30/2016 

I have cloudy water after super shocking the green out. Have ran pool pump constantly and clarifier twice but still cloudy ?
 Reply

InyoPools Product Specialist  Posted: 6/28/2016 

john - I think you are referring to the drain plug at the bottom of your sand filter and not sand pump. Check the parts list for you filter to see if you are missing an O-ring or gasket. Click "Replacement Parts"; find your manf and filter model; and look at the diagram of parts around your drain plug.If your model has no O-ring or gasket, try wrapping 4-5 layers of plumber's tape around the threads that the plug attaches to.
 Reply

 Posted: 6/27/2016 

at the bottom back of the sand pump their is a drain plug threaded I have thightened it as far as it will go and their is a leak at the top of the drain plug, no cracks that I can see, I have the right size threaded cap that goes with the pump not sure why its leaking??
 Reply

InyoPools Product Specialist  Posted: 6/26/2016 

jacki - It sounds like the spider gasket in your multiport valve is damaged and is letting waste water into the return port when you backwash. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" to locate and possibly replace this gasket.
 Reply

 Posted: 6/24/2016 

How do i backwash without getting the dirty water into my pool after the initial adding of new sand.
 Reply

 Posted: 6/24/2016 

I changed out the sand in my pool this year but when I turn the pump on to Backwash the dirty water from the tank goes into the pool. Do I need to close the inlet valve to the pool before backwashing. I dont want this dirty water in my pool.
 Reply

InyoPools Product Specialist  Posted: 6/22/2016 

closed filter overnight - Your filter is probably alright. I'd check the spider gasket in the multiport valve. See our guide on "How to Replace a Spider Gasket on a Multiport Valve". And your pump may have taken the hit. With no water flow, it had nothing to cool it. Watch for leaks around the pump gaskets and replace them if required.
 Reply

Anonymous  Posted: 6/21/2016 

I accidentally left my sand filter in backwash position overnight with ball valve closed on the waste line. Didn't realized until next morning when I realized the pump didn't sound normal. Pump was hot when I corrected the setting back to filter. Could I have damaged the sand filter. Pool water has been cloudy four days now.
 Reply

InyoPools Product Specialist  Posted: 6/20/2016 

Jessica - Do you have any water flow at all? Try putting you multiport valve in Recirculate mode which bypasses the filter. I no or little water flows, your problem isn't the filter. You have a block somewhere in your system. One of the most common system blocks is in your motor's impeller. See our guide on "How To Clean Out a Pool Pump Impeller".
 Reply

 Posted: 6/18/2016 

In my sight glass there's greens stuff in there what does that mean? I need help everything about my filter isn't working the filter itself won't do anything and neither will the backwash it just stays still and nothing happens it all started happening after I was vacuuming the pool and dirt started coming out of the jet holes so i stopped and tried to backwash it but nothing happened water wouldn't come out of the hose so I turned back to filter and nothing happened what do I do?
 Reply

InyoPools Product Specialist  Posted: 6/17/2016 

nccowboy66 - Depends on the size of your pool. If your recommended pump was 1.5 HP, 2HP is probably more than you need. But if you are maintaining 10-11 psi on your filter gauge, you are probably all right. It might also turn out that your 2.0 HP pump is close to your 1.5 HP pump. See our guided on "How To Understand True Pump Horsepower - Up Rated vs Full Rated".
 Reply

 Posted: 6/15/2016 

I have a Hayward S-210T and have had to replace the pump and skimmer housing with a 2Hp pump the recommended pump size is 1.5Hp have I made a mistake with the 2Hp pump My pressure stays around 10 to 11 psi and I backwash and rinse every time I vacuum or after the pump runs for a week or longer?
 Reply

InyoPools Product Specialist  Posted: 6/7/2016 

Dani - Check that nothing is stuck in the throat of the cleaner. Then check that the pump's impeller is not clogged. See our guide on "How To Clean Out a Pool Pump Impeller".
 Reply

 Posted: 6/5/2016 

I have a 13x27 above ground super splash pool, started up this year, everything worked great. then a week ago the vacuum didn't have enough suction to run the shark. Back flushed, rinsed, no help....any suggestions would be great!
 Reply

InyoPools Product Specialist  Posted: 6/2/2016 

Dee - You might have a damaged spider gasket in your filter's multiport valve, or you may have a cracked standpipe or lateral or lateral hub in the sand filter. See our guides on "How to Replace a Spider Gasket on a Multiport Valve" and "How To Replace a Lateral in a Pool Sand Filter".
 Reply

 Posted: 6/1/2016 

Hi y'all,

What does it mean when there is sand in the backwash?

Thanks!
Dee

 Reply

InyoPools Product Specialist  Posted: 5/30/2016 

jlmrww - Check for cracks in the standing pipe and hub of your lateral assembly. These could be letting sand into the laterals and clogging them.
 Reply

 Posted: 5/27/2016 

The filter setting on my pump isn't working - it will backwash and rinse, but nothing when it's on filter. The pump runs but nothing drains.
 Reply

InyoPools Product Specialist  Posted: 5/23/2016 

first time - Check the spider gasket in your multiport valve. It may be damaged and may be diverting water to the wrong place. See our guide on "How to Replace a Spider Gasket on a Multiport Valve".
 Reply

InyoPools Product Specialist  Posted: 5/23/2016 

From Dan - While Dan was waiting for a response, he was able to fix his problem himself and was good enough to provide this feedback. Thanks Dan.
"I got it fixed I took the pipe and fingers back out of the sand filter and found a crack in the bottom of the hub, replaced the hub, and cleaned the fingers and put back in. Working like a charm."

 Reply

 Posted: 5/22/2016 

Whenever I vacuum to waste, I was having a hard time getting my pump to prime when I turn it back to filter. I had it working, but just started to backwash and no water was coming out. Any suggestions are welcome!
 Reply

 Posted: 5/17/2016 

don't have a air tube it is a dream line sand filter system with a Haywood valve I can cot it off and mash down on the valve and let about a gallon of water out the waste and turn it back on and does good for a hour or so then same thing again
 Reply

InyoPools Product Specialist  Posted: 5/17/2016 

Dan - You may have backpressure building up in the top of your filter. If your filter has a breather tube from the bottom of the tank to the top, see if that tube is clogged. If it is clogged, it is not able to relieve trapped air in the tank.
 Reply

 Posted: 5/17/2016 

Start up season 15 x 30 above ground pool No problems last year Now it runs and does good for a couple hours then pressure goes to 20psi from 10psi and flow slows way down in pool.Changed sand,cleaned propeller,back-washed and rinsed Then starts back up good and after a couple hours does same thing.Water cloudy but not green Not dirty 175lb sand filter Hayward pump and valve????
 Reply

InyoPools Product Specialist  Posted: 5/16/2016 

leaking backwash - You may have a damaged spider gasket in your multiport valve. See our guide on "How to Replace a Spider Gasket on a Multiport Valve" to inspect and possibly replace this gasket.
 Reply

Anonymous  Posted: 5/14/2016 

After backwashing and putting value back in the filter position turn the filter back on sometimes the pressure builds up and water come out the backwash hose
 Reply

InyoPools Product Specialist  Posted: 3/16/2016 

Mimzie - Nothing is wrong. 10 psi is a good reading for an operating sand filter.
 Reply

 Posted: 3/16/2016 

I just purchased a house with a inground pool and I have the sand filter and it stays on around 10 psi while running on filter. is that correct or is something wrong?
 Reply

InyoPools Product Specialist  Posted: 11/3/2015 

HELPLESS - You may have damaged the spider gasket in your multiport valve. To look at this gasket and possibly replace it, see our guide on "How to Replace a Spider Gasket on a Multiport Valve".
 Reply

 Posted: 11/3/2015 

I am new to the pool ownership world and I may have messed up. I was cleaning my inground pool and forgot to turn off the pump before switching my sand filter to backwash. Now I can't get the pump to prime. When I fill up the pump with water it just flows back to the pool and skimmer, I can plug the skimmer and the pump will fill but I know that's not correct and the pump does create pressure but my system doesn't have a gauge. Just trying to figure how to get my pump to prime again? thanks!!
 Reply

InyoPools Product Specialist  Posted: 10/28/2015 

Cfran20 - Not sure what's going on here. As you say, a 4 psi rise should not shut done your system. Sand is only 1 year old so should not need to be replaced. Your filter is sized correctly for your pump. Is this happening at the lower pump speeds which may be more susceptible to clogged filters? Check that there is at least 6' of space between the top of the tank and the top of the sand. Also run your backwash / rinse cycle 3 times in a row to make sure your sand and laterals are clear.
 Reply

 Posted: 10/27/2015 

Hello, great video!! I have a Hayward sand filter with 350lbs of sand and a 1.5 hp ecostar Hayward pump. Normal pressure is at 18 psi and has been since installed last October. When pressure reaches 22 psi there is so little water moving you can't really tell the pump is running, once I back flush it drops back to 18 and runs fine. Replaced the gauge to see if that is the issue and same issue. Should a rise in 4 psi be enough to basically shut down flow? You reference a min of 10 psi before back flush is needed several times. Thanks for your help.
 Reply

InyoPools Product Specialist  Posted: 10/24/2015 

Jimmy - Depending on pool use and backwashing, the typical life of sand in a sand filter is 5-7 years. However, as your pool store indicates, as long as your pool is not turning green and the period between backwashing is not decreasing, your filter's sand is probably good for another year or so.
 Reply

 Posted: 10/21/2015 

My pool store told me that sand, depending on specific conditions, can last 5 to 15 years before it becomes worn out. They said the way to tell is check for a pressure increase of 8 to 10 psi over time (and backwash with this increase). If i'm getting this pressure rise and the backwash water is dirty, the sand is GOOD and doesn't need replacing. They say the pressure rise means the sand edges are not rounded badly and I'm still trapping debris. Is that information correct? My sand is about 8 years old, but I am getting the pressure rise and NOT wanting to replace the sand prematurely.
 Reply

 Posted: 9/4/2015 

Hello, great video!! I have a Hayward sand filter with 350lbs of sand and a 1.5 hp ecostar Hayward pump. Normal pressure is at 18 psi and has been since installed last October. When pressure reaches 22 psi there is so little water moving you can't really tell the pump is running, once I back flush it drops back to 18 and runs fine. Replaced the gauge to see if that is the issue and same issue. Should a rise in 4 psi be enough to basically shut down flow? You reference a min of 10 psi before back flush is needed several times. Thanks for your help.
 Reply

InyoPools Product Specialist  Posted: 8/12/2015 

Mugsy51 - No, there is no lock on the valve that you have to release to depress the handle. Sounds like something is stuck inside the MPV. Try taking the top assembly off of the MPV like you would do to replace the spider gasket to see what might be binding the handle. See our guide on "How to Replace a Spider Gasket on a Multiport Valve".
 Reply

 Posted: 8/11/2015 

I've watched your demonstration many times since I have to backwash my Pentair Triton II sand filter for the first time. In your presentation and others it seems like people just push down on the multiport valve and it goes down. I've been trying all afternoon with all my weight, but it just won't budge. Is there some kind of latch or do-dah to fiddle with first?
 Reply

InyoPools Product Specialist  Posted: 8/10/2015 

louie4 - Sounds like it's time to change your sand. Sand should be changed every 5-7 years. And if the standpipe assembly came up, you will have to pull the sand out anyway to reset the assembly.
 Reply

 Posted: 8/9/2015 

My Hayward sand filter is 6.5 years old. I backflush it regularly, but it doesn't seem to get itself clean anymore. There is no change in the pressure drop. Always about 28-29 psi. Thinking I had built up a layer of impermeable debris on top of the sand, I took the top off. Not much debris there. But the standpipe assembly came up through the sand with the top. Now what?
Is it time to drain the filter and replace the sand? Or just figure out a way to get the standpipe back down?

 Reply

 Posted: 8/8/2015 

8-8-2015 My compliments to you on the way you have your website set up. I watched your "How To" on back-washing a sand-filter and found it to be very, very helpful. I'll certain purchase items on-line from you as I get better, more accurate information from your site than the high school kids behind the counter at my local pool store. Thanks again!
 Reply