DE and Filtered Material Blowing Back Through Returns

[Gfunk720]

Good afternoon. Looking for a little assistance as I have been stumped for the last few weeks on what is going on with my pool. We opened at the beginning of June, and had an uneventful first few weeks. Around early July something changed and my pool started getting cloudy and needing constant brushing and vacuuming.

~18,000 gallon in ground pool w/ Vinyl liner
Purchased as is ~9 years ago, but equipment looks older than that
Hayward (36 CU/FT) DE Filter grids were replaced 2 years ago- Just cleaned and inspected them last week and found no issues

When the pump initially turns on, you can watch the returns blow out green and white crud. Even little pieces of filtered material that made it through the pump basket. After about 15-20 seconds it starts to dissipate, and after 60 seconds or so it appears to blow clear (or clearer). I've never noticed this before this year. My filter grids were a bit packed with DE when I pulled them(despite backwashing for 10+ minutes) but there were no tears or issues. The top filter vent appears clear and as it should. However, the filter does not appear to be doing what it is supposed to.

I just replaced the spider valve gasket this afternoon thinking that the filter medium was getting back into the returns, but on first start up it didn't really seem to make a difference. I'm a bit reluctant to change the whole filter assembly and spider valve, as I'm hoping that it is something easier. Any suggestions on other things to explore?

 

[1poolman1]

Good afternoon. Looking for a little assistance as I have been stumped for the last few weeks on what is going on with my pool. We opened at the beginning of June, and had an uneventful first few weeks. Around early July something changed and my pool started getting cloudy and needing constant brushing and vacuuming.

~18,000 gallon in ground pool w/ Vinyl liner
Purchased as is ~9 years ago, but equipment looks older than that
Hayward DE Filter grids were replaced 2 years ago- Just cleaned and inspected them last week and found no issues

When the pump initially turns on, you can watch the returns blow out green and white crud. Even little pieces of filtered material that made it through the pump basket. After about 15-20 seconds it starts to dissipate, and after 60 seconds or so it appears to blow clear (or clearer). I've never noticed this before this year. My filter grids were a bit packed with DE when I pulled them(despite backwashing for 10+ minutes) but there were no tears or issues. The top filter vent appears clear and as it should. However, the filter does not appear to be doing what it is supposed to.

I just replaced the spider valve gasket this afternoon thinking that the filter medium was getting back into the returns, but on first start up it didn't really seem to make a difference. I'm a bit reluctant to change the whole filter assembly and spider valve, as I'm hoping that it is something easier. Any suggestions on other things to explore?

Be sure all grids are seated properly in the manifold. Be sure the long rod that holds the grid cluster together hasn't come loose. Be sure the air-relief screen is in place on the manifold and not missing or damaged.

 

[Gfunk720]

Be sure all grids are seated properly in the manifold. Be sure the long rod that holds the grid cluster together hasn't come loose. Be sure the air-relief screen is in place on the manifold and not missing or damaged.

I've had it apart twice now and confirmed they were all as they should be. Re-tightened the top nut as well. Checked the air-relief screen, but maybe I need to give it a more thorough look.

I just went out for a while after replacing the spider valve gasket and shut it off for about 30 seconds. Turned it back on and had about 5-10 seconds of blowback into the pool. It almost seems to be getting worse, where before once the filter was running it would eventually clear it up.

 

[Gfunk720]

The pool has been slowly clearing up with near 24 hour pump running. I was getting DE out of the returns in big poofs at startup for a while, but that seems to have subsided a bit. I still have quite a bit of DE in the pool though, and even when I vacuum it up it just comes back again. The pool also looks clear until someone goes in it, or I brush it a bit, and all of the DE powder gets stirred up and the water gets cloudy again. I've been checking water chemistry weekly and everything is spot on.

I pulled the filters this morning again and checked all of the grids and found no issues. They are seated properly, have no tears or holes, and are in very good shape. The air relief screen is in place and undamaged, and aside from having DE on it looked normal. I'm at a little bit of a loss, and the only thing I can think of at this point is to replace the multiport valve or filter. I just can't seem to figure out where the DE is getting in, and through my professional background don't just want to change parts. Throwing a few thousand dollars at it only to potentially have the same issue, or finding out it was something simple just isn't how I want to approach the situation.

1. Is it possible one of the other gaskets or a worn out spring in the multiport valve are letting debris and DE through? I remember it having a lot more resistance, and really having to push down on it to get it to spin, and now it still seems fairly easy even with the new gasket. It also used to make more noise when turning, like the rubber seals were more audible.

2. I didn't thoroughly clean out the filter housing previously. I think I'm going to do that today, but figure anything down in there would be caught by the filter grids anyway.

3. I grease and checked all other seals, such as the manifold seal and the seal on the lid of the filter housing. Any others that may be letting DE through?

Any assistance is appreciated. While I'm tempted to call my emergency pool guy, I'm guessing he's just going to want to replace everything rather than getting to the root of the issue. I have pictures of everything if they are any assistance.

 

[Gfunk720]

In case anyone is having a similar issue now or in the future, I took everything apart again and started checking the piping inside the filter housing. I ended up taking off both of the inlet and outlet pipes, and found a sizeable crack in the outlet elbow from the radius of the 90 back through the threads. It was on the bottom of the elbow so I couldn't see it until I took it off. I knew it was something relatively simple as there aren't a lot to these filters/diverter systems. I'm guessing any pool company would have just told me I needed a new filter.

New part ordered and on the way with fresh O-rings. Debating whether or not to patch it up with some PVC glue to see whether I can run for a few days until the new part comes.