Have to backwash every five days???

[kodiak1120]

I have a DE filter. In past season, I would backwash maybe once per month. For some reason, lately I've had to backwash every five days. Basically, I notice that the water pressure out of the return jets is diminished. When I check the filter, the pressure is up to 24 PSI. After I backwash, it drops to 12 PSI before I add DE, and then about 14 PSI after I add DE. The water pressure is restored after I backwash, but then about four or five days later, the pressure goes back up to 24 PSI and I have to backwash again. Any ideas? I suppose I should take apart the filter and see if anything weird is going on.

Thanks,

Kevin

Edit: I should note that the pool isn't getting any more use than usual.

 

[tim5055]

My first suggestion is to conduct an Overnight Chlorine Loss Test to see if something is growing in the water. DE filters capture almost everything and early in an algae bloom they can clog quickly.

 

[kodiak1120]

I can give that a try, but I'd be surprised if that was it because the water is crystal clear and in order for enough algae to frequently clog the filter, I would suspect it would be somewhat visible in the water.

 

[Richard320]

I can give that a try, but I'd be surprised if that was it because the water is crystal clear and in order for enough algae to frequently clog the filter, I would suspect it would be somewhat visible in the water.

I wouldn't. But the other possibility is that you never completely backwash all the DE away and then when you recharge it gets overloaded. A teardown and cleaning will eliminate that possibility. Doesn't even have to be a complete disassembly. I usually backwash briefly, then open the filter and blast the grids with a spray nozzle to knock everything off, reassemble, and finish the backwash.

An extreme case of what I'm talking about:

 

[kodiak1120]

I took the filter apart... like an idiot, I forgot to backwash it first though. Here's what it looked like Kind of strange how green it was. Not sure if that's normal, since I always backwash before disassembling. I had a rope separating the shallow end from the deep end and I noticed that the fibers started coming apart earlier this year. I replaced the rope, but it looks like a lot of the old rope was left in the filter, even after several backwashes. Not sure if that was part of the problem, but I disassembled everything, cleaned it all out and reassembled. Pressure is great so far.

Edit: You can see that the hose coming out the top was particularly covered in rope remnants and crud.