Backwashing DE Filter

[speyedr]

All good stuff. For myself, I cleaned the filter at the end of last season and will do so again this year. I like to start fresh and, as Steverino said, it did not take long.
Once the pressure reaches the backwash point, or my pool is spotless (whichever comes first) I will backwash and then open the filter to see what is left. That way I'll have a baseline, however inaccurate. I can still ball park it, and I did not have to backwash at all last year as the pressure never really rose. Even if I do it 3 or 4 times this season, with annual clean ups I suspect I will not build up too much.

 

[geekgranny]

The kind of clogging that appears in geekgranny's pictures would show up as a change in the "clean" filter pressure.

The picture illustrates what caused "clean" pressure of 14 psi to rise to clean pressure of 19 psi doing only very lengthy backwashes using way too much water. This was after 1.5 years with one swamp cleanup. (I tore a shoulder rotator tendon during the swamp cleanup and acid wash so I skipped doing a good cleaning which I usually do twice a year.) After a thorough, dishwasher soak and then acid soak and replacement of four grids the clean pressure only went down to 16 and with faster than usual pressure rise requiring more and more backwashings. I'm pretty sure that this was due to the broken nibs on the manifold not keeping all the grids in proper alignment. That's why I always chime in on threads to check the retaining nibs on manifold. I'd been managing the filter for 22 years and it always went back down to 14 psi after good cleaning/soaking but this was the first time I had the broken nibs so I'm pretty sure that's was caused the change.

BTW... I'm really enjoying the new big filter 36 sq ft to 80 sq ft makes a HUGE difference!!!!!!!!!!!!!!

gg=alice

 

[eostrike]

What do you do with the DE when you clean out the filter. Is it safe to leave in the planter or wash down the street? I only ask as when it is in powder form it could be hazardous to your health. I assume when it comes out it will come off in clumps but at some point wouldn't is dry up and start to turn back into power? This is a newbie question, thanks in advance.