Pumping lots of DE back into pool

[bud_ugly]

The filter is a Purex Triton FNS Plus 48 for an in-ground pool.

Over the last couple of months a layer of DE has begun to cover the pool bottom. When vacuuming, the DE just pours back into the pool from the returns. Adding fresh DE after a backwash results in the same. I inspected the filter grids and they do not appear to have any obvious tears (though they are 12+ years old and appear to be installed properly. I first noticed this last year after a filter cleaning though it only allowed a small portion of the DE to enter the pool then. Now it acts as if there are no filter grids...

To me, the likeliest thing looks like the filter grids even though I cannot see any obvious damage. Can anyone think of any other possibilities I should be considering?

thanks,
-bud

 

[Bama Rambler]

The grids are the most likely place, but the manifold seals could be leaking by. The multiport could be leaking but that's not likely.

 

[Beez]

Is the screen on the manifold intact? Just replaced mine because of similar problem.

 

[bud_ugly]

Thanks for the replies guys, both warrant further investigation. I'm not an expert in this sort of pool maintenance so please bear with me if my further questions seem dumb.

@ Mod Squad: Manifold Seals? The grid ends are well seated into the manifold (made that mistake before). Are there supposed to be o-rings or some other type of seal? I don't recall anything other than that grid/manifold placement template in that area. If there were seals, they must be long gone...

@ Beez: Manifold Intake Screen? I don't recall ever seeing any screen on the manifold intakes nor the output. Are the screens built into the manifold? Maybe I just never noticed them before...

thanks,
-bud

 

[Beez]

@ Beez: Manifold Intake Screen? I don't recall ever seeing any screen on the manifold intakes nor the output. Are the screens built into the manifold? Maybe I just never noticed them before...

What I am referring to is called the Internal Air Bleed. Here is a link to a picture. The link points to the replacement, so yours may look a little different. It is basically a tube that sticks up from the manifold, has some type of screen on the end. Check to see if the screen is damaged or even missing.

 

[bud_ugly]

Thanks Beez. I'll look into that. I know mine does look different, it is tpaered and appears more cone shaped. I've never noticed a screen on the end of it in years past. When I rea the filter apart again I'll look at it more carefully.

 

[Beez]

Thanks Beez. I'll look into that. I know mine does look different, it is tpaered and appears more cone shaped. I've never noticed a screen on the end of it in years past. When I rea the filter apart again I'll look at it more carefully.

Oh, I assumed that your filter and mine were similar because of the FNS Plus. So yeah, my advice may not apply at all.

 

[thepoolman]

If you see a tapered cone shape, your screen is gone. They have been through a couple different designs in the last couple years and one of them was a cone with a piece covering it that let air out. They are back to a stainless mesh screen now.

 

[bud_ugly]

Thanks for the tip poolman. Sounds like I should be replacing that and the grids (the plastic forms inside are starting to breakdown).
-bud

 

[bud_ugly]

Replaced the Air Bleed (old one looked intact but aged) to no effect. I guess replacing filter grids is the next step...

 

[bud_ugly]

Replaced filter grids and all seems to be operating normally.
-bud