Sand Filter and Water Return

[Uncle Flappy]

In testing the effectiveness of the sand filter, I poured a small amount of stabilizer into the skimmer and a portion (but but not all) of it came back into the pool from the wall return. I haven’t seen any sand in the pool so doubt that a lateral is broken; however, all other attempted troubleshooting did not prevent similar results. I disassembled the backwash valve to ensure the O-rings were good – no problems there. I also did a deep clean on the sand to rule out any channeling.

What next? Should I remove all the sand to visually inspect the internal components or is some loss expected?

Thanks for your help.

- Flappy

 

[duraleigh]

CYA will not travel through a working sand filter.....something is not working......not sure what that is aside from a broken lateral.

 

[Uncle Flappy]

That's what I was afraid of. Looks like I'll be busy scooping sand next weekend.

 

[JamesW]

If you're not getting sand back into the pool, then I would suspect the multiport or the internal air relief inside the filter.

Try this, screw a fitting into a return and then put a kneehi stocking over the fitting with a rubber band to see if it catches any sand.

 

[Uncle Flappy]

If you're not getting sand back into the pool, then I would suspect the multiport or the internal air relief inside the filter.

Try this, screw a fitting into a return and then put a kneehi stocking over the fitting with a rubber band to see if it catches any sand.

I'll give that a try at various pump speeds. FWIW, I don't have a multiport valve - it is just a backwash slide valve and it checked out ok.
The air relieve intrigues me - I'm not familiar how that works.

 

[JamesW]

It's a plastic tube with a screen over the end. It should poke up through the diffuser and be near the top threaded in dome.

 

[Uncle Flappy]

It's a plastic tube with a screen over the end. It should poke up through the diffuser and be near the top threaded in dome.

Maybe that's the issue? There is a plastic tube and it slides through the difuser but there isn't a screen on the end. It is wide open...

 

[JamesW]

PENTAIR

The tube goes into the return pipe after the laterals. If it's open, then you will get some debris bypassing the filter. There are two different strainers depending on the date of manufacture. See the parts list above.

 

[Uncle Flappy]

Sounds like we are on to something, thanks, and the prospect of avoiding scooping sand has me giddy.
Just so I am clear, is it just a fitting that needs to sit on the end of the hose or does it actually attach to the dome? Right now the hose slides through the difuser but it is open-ended.

Edit: Looks like that very well could be the issue. Sounds like I need one of these:

 

[ahlambz]

what size of sand filter and pump I need for 9x4.5 mtr pool of water depth 0.80 to 1.60 mtr
Thanks for your help.

 

[JamesW]

That's the part you need. If it's a newer filter, then you need the screen that fits the 3/8" tubing. If it's older, then you need the screen that fits the 1/4" tubing.

The 3/8" is used on filters manufactured after 11-1-99.

The screen just pushes onto the tubing and does not attach to the dome

 

[Uncle Flappy]

I orderd the 3/8" (pool built in 2003), thanks! Hopefully that will resolve the issue.

 

[Uncle Flappy]

Closing the loop on this. I installed the screen and that did indeed resolve the issue. Unlike last time, adding a small amount of CYA in the skimmer did not result in any of it back out the return.

Thanks for all the help!

- Flappy

 

[JamesW]

Good job. Thanks for the update.

 

[duraleigh]

Nice work! Thanks for the update.