Backwash question

[Maxomom]

Hello! I switched to cellulose fiber filter medium for my Pentair FNS 48 DE filter some years ago. The last time I did a full filter cleaning, and having done one backwash a number of months prior to the full cleaning, I noticed that there seemed to be a scant amount of the cellulose fiber remaining on my filter panels.
Pentair says to do 3 full backwash cycles and then add 8 cups of fiber after backwash - 12 cups after complete cleaning.
So my question is should I consider either 1) doing less backwash cycles or 2) perhaps adding more replacement cellulose than what is recommended in order to ensure enough filter medium remains on the panels after backwash ?
Just want to make sure I am getting proper filtration year round. Thanks!

 

[splashpad]

@Maxomom
We have a sand filter, not De, but these are the questions that come to mind for me:

• What is the PSI on the filter (clean & 'dirty')?
• What is the recommended PSI in the manual?
  • That should give you a general basis for determining the amount to add for appropriate filtering (track how much you add to achieve the recommended PSI)

Hope that helps some!

 

[Jimrahbe]

Max,

I suspect the grids are coated just fine.. When you open a filter the DE/fiber will often slough off and fall to the bottom of the filter.

If the grids were not coated, they would have a lot of debris caught in them.

But.. I can't see where adding a 10 cups, after a backwash, will hurt anything.

Thanks,

Jim R.

 

[Maxomom]

@Maxomom
We have a sand filter, not De, but these are the questions that come to mind for me:

• What is the PSI on the filter (clean & 'dirty')?
• What is the recommended PSI in the manual?
  • That should give you a general basis for determining the amount to add for appropriate filtering (track how much you add to achieve the recommended PSI)

Hope that helps some!

Thanks for your reply... normal PSI is 19-20 ... I typically do a full cleaning at least once per year or when the PSI creeps above 25. Will occasionally do a back wash after I’ve done a chemical treatment, for example an algaecide when I’ve been inattentive to my pool chemistry . ( yes, happens to the best of us...?)

 

[Maxomom]

Max,

I suspect the grids are coated just fine.. When you open a filter the DE/fiber will often slough off and fall to the bottom of the filter.

If the grids were not coated, they would have a lot of debris caught in them.

But.. I can't see where adding a 10 cups, after a backwash, will hurt anything.

Thanks,

Jim R.

Thanks Jim! That’s what my instincts told me and I sincerely appreciate your reply.