DIY Sand Filter - Will This Work?

[PoorDad]

We have a little 650g above ground pool for the kids. The pleated paper filter that comes with it is basically useless.

I'm trying to build my own sand filter using a 5g bucket. Please take a look at this drawing and let me know if this will get the job done.

During normal operation, water would drain from the pool outlet and into the sealed lid on the 5g bucket. There's sand in the bucket and a strainer at the bottom to keep the sand from leaving the bucket. Water flows through the bucket and into the pump. Water is returned to the pool.

Green lines are ball valves. During normal operation, the valve on the top purple line would be open to allow water to drain out of the pool and into the 5g bucket.

Also on top of the bucket, there's a Tee line and a ball valve that would remain closed during normal operation. This is my waste line and would only be opened during back flush.

There's a couple ball valves to isolate the pump during back flush. I plan to back flush with water pressure from the pool. During back flush, I'd close the ball valves on either side of the pump to take it out of the loop. Open the valve on the cross line above the pump. Open the valve on top of the bucket so water can flow out the Tee line. That will essentially allow the sand filter to back flush using head pressure from the water in the pool.

Open to suggestions and criticisms. Thank you.

 

[PoorDad]

First pic is with valves set to back flush.

Second pic is with the valves set to normal operation.

Hope these pics help.

Thanks for any help

 

[Richard320]

I suspect that the pump will need more flow than a gravity feed will provide. So you'll end up overheating the pump, or imploding the bucket. Reversing the lines will probably just cause the bucket to explode.

Check eBay, or craigslist for an old filter. Call any pool stores in the area. They may have something that's scratched, or was left for repairs and never picked up.

 

[rv4hess]

Hi PoorDad,
I don't think that will work. From what I know about our sand filter system, The pump draws directly from the pool and pressurizes the filter to push the dirty water through the sand. This pressure can potentially reach 25-30 psi or more which converted to the area of a 5 gal bucket would be a little bomb, probably similar to sealing a milk jug to your garden hose.
Your proposal of letting water drain through a bucket would not let enough water through fast enough to run your pump.
You may find some creative minds around here to come up with another plan but I would guess you could find a used filter somewhere like craigslist that would be a lot less headaches.

Best of luck,
John

 

[PoorDad]

Thank you for a quick answer. I appreciate it. Never even thought to check craigslist. Going there right now.

 

[solarboy]

You can get cheap filter/pump combo's to upgrade the ones that come with Intex style pools. The pressure in something homemade is going to be enormous and you'll also need to design some kind of laterals. You could maybe try something that is an "open" bucket, placed at the top of your pumps "head", ie attach a pipe to your pumps out let and hold it up higher and higher till the water just trickles out. Then place your bucket at this hieght. The bucket could have a hole in the bottom with a pipe coming through, well sealed with a quality sealant and then once the pipe is in the bucket add a "T" and drill some holes in 2 short pipes to form your "laterals". The water could then just fall under gravity back into the pool. If the bucket was big enough (a drum?) you'd only need to clean once a season so you could just hand wash the sand at the beginning of the season.
Hopefully you'll find something cheap and second hand, I have one you could have but I'm in Portugal ! but I would have thought someone involved in pools would have something for you.
Good luck with your project.