How To Clean Swimming Pool Sand Filters..Backwashing

The swimming pool sand filter is not working properly. It's not backwashing at all.

I'm not sure what the problem is and hope you can help out. I lost my manual and not sure how to get another one.

We have a Maxi Plus 160 sand filter, hope you can give me some insight on this.

Thanks for your question

Check the Multi-Port Valve to ensure that is working correctly. Any leaks might indicate a bad O-Ring. When you put the setting to BACKWASH or RINSE, does it "click" in place, or does it have a smooth feeling? If there's no click, the valve or inside diaphragm (spider gasket) might be worn out.

Be sure the pump motor basket and skimmers are free of debris.

Try removing about 1" of the top layer of the sand, replace with the exact amount of sand you removed. This is where alot of grease, gunk, and debris can hide. Normal life span of the sand is about 4 - 5 years.

I would ask how old the swimming pool sand filter media is? If it's over 10 years old and the pool has seen regular use, it might be time to change it out. If the sand media needs to be changed, look for broken laterals and replace if needed.

You can go online and order another owner's manual, which is very simple to do.

If the sand media is o.k., then check to see if it has the correct amount of sand. You can check with the manufacturer as to the amount of sand. Also check to see the clearance in inches, from the top of the sand filter to the top of the sand to ensure you have enough.

You can also check for channeling. This is when the pool water will flow down the sides of the filter, rather than through the sand. Channeling occurs when the sand media becomes clogged with grease and debris. You'll need to degrease the sand filter.

The product I use at the Y is "Filter Fresh". Any pool supply store should have this. Turn off the pump motor, open the top of the sand filter, shake up the bottle of Filter Fresh, and pour the content straight into the filter. Allow this to sit overnight.

In the morning you'll want to top off the filter with water. Be sure to screw the top of the filter on and start the pump in BACKWASH mode to get all the gunk out, then RINSE mode.

Allow your pool sand filter to run for about a day or so and try to backwash again.

Good luck and let me know how this works for you

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Dirt Pumped Into Pool When Switching On Pump - Sand Filter System

by Patrick J
(South Africa)

When the pool pump is turned off there is a loss of pressure and water returns to the pool from the filter.

When the pool pump is switched back on there is air in the system and the pump has to be re-primed, then there is air pumped into the pool with a great deal of turbulence.

This is followed by a stream of dirt which eventually clears and the system then functions normally until the next cycle when the scenario is repeated. The result is the pool never clears properly and dirt settles on the floor where the Kreepy Crawly doesn't go.

What would be the cause?

Thanks for the question Patrick

When dirt enters the pool through the returns with a sand filter, it could be the following:

1. Broken lateral
2. Too much or too little pool sand media
3. Channeling

More times than not it's a broken lateral. You might need to scoop out the sand and replace the lateral(s).

For the loss of prime I would check the obvious first:

1. Bad, old, or broken Multi-port Valve. Check the gasket or O-ring. Turn the pump off and switch valve positions. If it doesn't "click" nicely in place you may need to replace it.

2. Gasket around the pool pump motor lid. If broken or worn replace it.

3. Look for obvious wet spots on and around the filter and ground. You might have a leak that is drawing in air.

4. The return line(s) might be cracked. Easy way to find which line is with the pump running, open the skimmer valve all the way and close the main drain valve. If there's a loss of suction the problem is the skimmer line.

Close the skimmer valve and open the drain valve. Again if there's loss of suction, it's the drain.

5. With the pump off check the pump motor impeller
for clogs or debris. Be sure the keep the pump basket and skimmer basket clean.

6. There is also the mechanical seal in the pump motor. A mechanical seal is a seal which helps join systems or mechanisms together by preventing leakage. I've replaced a few of these on the pool pump motors at the YMCA when we've had a leak, but the motors run 24/7.

Hope this helps and let me know how it turns out for you

Best of luck


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Sand Filter Help..Filter Won't Work After Vacuuming

by Sue
(Wixom, MI USA)

I have a Kayak pool with a Sand Dollar filter.

Last year, the filter was working fine. After vaccuuming the pool, the filter would not work properly.

It wasn't getting up enough pressure.

I replaced the ball valve (@$140.00), and all was working well, til I vaccuumed again.

Now it won't build up pressure again.

I have no idea what I'm doing wrong.

This is my 10th season with this pool and this system and I just can't figure this out for the life of me!

Thanks for the question Sue

Here's a good post to start with. It has a cartridge filter, but the troubleshooting is the same.

Maintaining Vacuum Suction..Loss Of Suction With A Cartridge Filter..

Does the system lose pressure while you're vacuuming? If it does, it could be a crack or hole on the hose.

How do you know there's no pressure? Do you check the pressure gauge or is there no water in the pump pot?

An easy way to see if the gauge is working is to turn the system off. If the needle sticks, the gauge is probably bad and needs to be replaced.

If the needle drops to zero, you may have a suction side or skimmer leak.

Be sure the water level is up 1/3 - 1/2 from the bottom of the skimmer.

Here's another good post:

Why Is Air Getting Into The Sand Filter & Pump?

Here are other things to look for:

*Low water levels

*Skimmer weir stuck

*A broken suction line from the skimmer to the pool pump motor

*Loose pump lid or bad gasket

*Loose fittings in and out of the pump

*Clogged pump basket

*Worn our pump seal

*Bad or old sand. Maybe it needs to be degreased.

All these might allow air into the system.

Check out this post. A little long, but lots of good stuff:

How Do I Fix Low Skimmer Suction?

If you have more than 1 skimmer, you can try this, but be very careful.

Turn the system off.

Slowly close the valve you normally vacuum with and leave the other valve open.

What you're doing is closing off a valve and forcing the other one to do the job.

Turn the system back on.

If you don't lose suction or water in the pump pot, the other skimmer is fine.

Do the same, only opposite. Open both valves, then close the one you DON'T vacuum with and leave the other one open.

If you do lose suction or water flow, then the problem is the suction in the skimmer.

If you vacuum from the skimmer, this might be the problem. Either a broken line or clog.

Then it's time to call a repairman.

Try that along with the links above.

Hope this helps and have a fun and safe Summer.


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