DE in sand filter making high PSI

WDE4Life

Member
Mar 30, 2020
6
Birmingham AL
I am a newbie here but read a lot of articles. I read one on adding DE to your sand filter to improve fine particle filtration. I get a good bit of fine "dirt" that settles in the creases and crevices of my liner so I thought I would try to add a little DE to improve filtration. I followed the article on here on how to add 1/4 cup at a time until it raises PSI by one. For my filter that was 1 cup. The problem is that a few hours later my PSI was up by 8 PSI. I read the article again and it said
" The very first time you do this, you should keep an eye on the filter pressure for the next 24 hours or so. The improved filtering may quickly catch a lot of very fine particles and send the filter pressure up rapidly. "

so I backwashed and PSI was back to normal. I added 1 cup again, again it raised PSI by one and then 2 hours later it was back up 8 psi. So again I backwashed and its back down to normal (15PSI)

So my question is what do I do next. Keep doing this experiment? Or add less DE to my sand filter? Or just leave it alone and deal with the fine sediment.

Chlorine is at 8 CYA is at 70 PH is 7.8 SWG is running 40%
 

Richard320

TFP Expert
LifeTime Supporter
Jan 6, 2010
23,930
San Dimas, CA (LA County)
Until you filter it all out, it's going to keep doing that.

That is, if you can filter it all out. "fine dirt that settles in the creases and crevices of my liner" sounds a bit like algae. If the water is the slightest bit hazy or dull looking, you're probably on the edge of an algae bloom. Sometimes the chlorine and algae reach a stalemate, and you end up with a neverending supply of dead algae to filter out. And that will clog a DE filter in hours, as you've discovered.
 

WDE4Life

Member
Mar 30, 2020
6
Birmingham AL
Until you filter it all out, it's going to keep doing that.

That is, if you can filter it all out. "fine dirt that settles in the creases and crevices of my liner" sounds a bit like algae. If the water is the slightest bit hazy or dull looking, you're probably on the edge of an algae bloom. Sometimes the chlorine and algae reach a stalemate, and you end up with a neverending supply of dead algae to filter out. And that will clog a DE filter in hours, as you've discovered.
Thanks. this sounds exactly like what I have going on. So I guess it’s SLAM time.
 

sktn77a

Gold Supporter
May 16, 2010
1,887
Chapel Hill, NC
I had some serious filtering to do earlier this summer - added sparkle up (cellulose - similar in principle to DE) to my sand filter and had to keep back washing every couple of hours. Ended up adding about 1/8 of the recommended amount and that ran for 12-24 hours before needing to be back washed. The higher recommended amount definitely filtered out the particulates better but there's a balance to be had between filtering efficiency and wasting the cellulose/DE.