High Pressure after cleaning filter manually

I cant figure this out. After backwashing my DE-4800 filter several times, my system starts at 12-15psi with great flow for a couple hours. then creeps back up to 25 or higher and eventually flow slows to a crawls. I then tried manually cleaning the fliters and starting the system again. Same thing, started at 12 psi with GREAT flow for 2 hours. I let it run over night… and after 6 hours psi jumped back up to 25 psi and flow has slowed again.

I notice when I look inside the pump skimmer when I start it with great flow the pump is full of water… but as the but after a few hours it look like it get about half full… I am beyond frustrated…

Before I go and buy a new filter grid to see if that help, I thought I would see if anyone has any suggestions. Thanks!

Hi Butter, We have dicussed this issue with a couple of the manf service reps and based on those discussions offered this explanation to several customers in response to Comments. Comments aren’t set up for feedback so I haven’t got anything back for customers that may have tried this.  One possible cause of a gradual reduction in water flow is a buildup of air pressure in the top of the filter tank If you have a closed system, air cannot enter into the tank, just water. But if you have a suction leak at or before the pump. air will get sucked into the system and be collected at the top of the filter tank.Over a short time, this air will cause a substantial buildup in backpressure which will impede the flow of water through the filter. When you do a Backwash, your will release this pressure. Returning to “Filter” will restart the air buildup cycle, One indication that you have a backpressure comes when you turn off the pump. If you have a strong surge of water shooting back through the pump and out the skimmer, it’s the immediate release of this backpressure. Some customers have seen a column of water blow the skimmer cover off after shutting off the pump. The solution to this problem is to isolate and correct the suction air leak. Here is a Guide on On How to Insolate and Correct Suction Leaks which you may find helpful.

I have the exact same problem. I replaced all the filter grids. However, I ran the filter WITHOUT the grid installed and it functioned perfectly, no pressure build up and the flow was great. Once I reinstalled the brand new and clean filter grid, the same thing happened, high pressure builds and the flows nearly completely stops.

I have a similar problem but I dont have a cartridge filter. I have a brand new DE filter that runs fine for the first however long and then slowly the pressure on the filter goes up and you start to see air bubbles in the pump. I have replaced the gaskets, as I have been told there may be a air leak before the pump. This is just super weird this is happening all after I just purchased a new filter. Any suggestions?

I have same issue, I also tried new de filter grids without any success. Did any one found solution?

I also have this problem. Did any of you determine the cause?  I’d like some advice on it. Of late, my starting pressure is unusually high, and I have been experiencing very short filter cycles - as in only 4-5 days before needing to backwash again due to reduced flow. This is maddening cause I’ve never experienced this before. I use biguanide and so understand the issues associated with it - the white water mold, etc. - I’ve dealt with all that, but this is a different problem the way it seems. When I take apart the filter after the flow is reduced, all I’m seeing is DE. I know what the mold and slime look like, and there is very little there.

Tonight, after backwashing, I turned on the pump before adding DE and, to my amazement, the pressure was only one pound less than before I started - already at 19 and it was only slightly above 20 before backwashing this morning. This makes no sense to me, and I can’t believe that this is all attributable to biguanide chemistry-related issues as I’m being told on a well-known pool website.

My typical starting pressure over the 30 years I’ve been running the pool has usually been around 11. This season, however, it is always around 13-15 - is gradually getting higher though - and now tonight was 19. I suspect I’ll be doing all this again in a few days, maybe even tomorrow?  What I do want to do next time is to run the system without putting the grids in. I’ve done this whenever we’ve gone on vacations during the pool season. The pressure stays constant at 10-11. IF it is now suddenly higher, then I know there must be some sort of mechanical issue. If, however, the pressure is as low as usual and only is elevated once the grids go back in, then I suppose it COULD be the grids but I’ve been chemically cleaning them (I have two sets so as to alternate) and doing everything the same that I have been for 30 years.

Any thoughts? Could there be a build-up of organic matter in the lines?  An issue with the pump?  I recently bought a product called Baquacil Line Cleaner and plan to use that. My gauge is new - I bought one of those glycerin-filled gauges to start the season - it’s calibrated in half-pound increments and has a larger face. I assume it’s showing me the right pressure (?) Never used one of these before.

Thanks so much for any advice or suggestions.