Can a return side leak cause DE to enter the pool?

[threecheese]

Hi,

I have a 'DE in my IG pool' issue. I have followed the remediation steps found in this forum and elsewhere, including:
- fixing a suction-side leak (the pump now runs with no bubbles/cavitation once primed)
- replacing the multiport valve
- replacing (most of the) filter grids, the manifold, o-ring, and fixing a suspected leak in the standpipe in my *very old* stainless steel filter.

This has not solved the problem. The easy next step is to replace the filter completely, as it is old as heck. However, I have a return side water leak when the system is under pressure and am trying to avoid fixing it as it will be a complete teardown (and it's a small leak). From what I've read, return side leak is not listed as a suspect for this issue. Is this wrong?

I don't know if this is relevant, but the DE in the pool is of a grey color, but when the DE goes into the filter it's white and when it comes out in backwash it's yellow, so I don't know where grey comes from

Thanks so much!

 

[Pool Tool]

Are you really sure what you are seeing in the pool is DE? A return side leak would have no way to introduce DE to the piping or pool in and of itself. Return side leaks do not suck things into the pipe like a suction side leak can sometimes. Even then your piping would have to be running through a pile of DE for it to get into the pipe somehow. So I don't think they are connected.

I would try to determine what is in your pool. It's more likely that it is dead algae or pollen or ?? than it being DE from the color you describe. Sounds like you have been thorough going thru the filter. Some folks have used a hairnet secured to the return jet(s) to catch material coming out of the filter. That might help see if it's really DE or just dead algae. An OCLT will tell if you if algae is present as well leading credence to dead algae vs. DE.

Sorry not many answers, but just a few thoughts. I hope it helps.

 

[JoelFitz]

Any leak in a closed system can cause DE to return to the pool. Just try it by turning off your pump and opening the air relief on the filter (if one exists). If this is the case then you'll find DE residual in the pump basket. The filter will empty and it's much less restriction going through the pump than through the return manifold. You'll also find DE around the main drain or in and around the skimmer if this is the case as well.

If the problem lies with the diverter (spider) gasket in the multi-port (backwash valve) or the grid assembly you can add a scoop of DE to the skimmer with the pump running and look for it to come back through the wall returns. I see you have a Polaris so check the in-line filter screen for DE residual.

GL!

 

[threecheese]

Thanks for the wisdom, I will be playing with the bleeder valve at first light.

 

[threecheese]

Joel: The pump basket turned white!! This definitely means it's the filter? I wish I had learned this trick earlier, would have saved some dough!