First DE Clean... PSI never returned to same level?

nemeth8

Well-known member
Aug 27, 2018
101
Plano
So I did a full DE filter clean.... took it apart and knocked out all the old medium.... re-installed and added back the correct/suggested amount. I noticed that my psi never returned to where it normally was (12 PSI and about 17 when a backwash was required)... and instead is at about 8 psi. Should I add more medium into the filter or just assume this is now the new 'normal?'
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,256
Tucson, AZ
Sounds like your actual true clean pressure is 8 PSI. So you should let it ride. I have noticed that the pressure before adding the de and after adding the de is usually very similar.

By the way we recommend cleaning your filter when the pressure Rises 20 to 25% over the clean pressure. For you that would appear to be at 10 psi now.

Personally, I don't backwash anymore because it never gets the grids fully clean and you should certainly not add the full amount of De if all you do is backwash. I just tear it down once or twice a year when it needs cleaning
 
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nemeth8

Well-known member
Aug 27, 2018
101
Plano
Not an expert on DE. Do you have a MPV or the bump style DE filter? If the Bump style then most probably there was old DE clumped together making pressure rise.
I do not know! I would guess you are correct with the bump style because the amount of DE I found in there even after back washing seemed like a lot. I think I will go with jblizzle's advice and just stick to breaking down and cleaning a few times each year.
 

Flying Tivo

Well-known member
Jan 24, 2017
1,070
Monterrey, NL, Mexico
If you were able to backwash then you have a MPV Valve. Those are the ones that read : closed,recirculate,filter,backwash, rinse,etc... Also make sure you add the DE correctly, mixed as a slurry and pouring slowly on the skimmer.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,256
Tucson, AZ
Does your filter have 8 grids or four canisters or a whole bunch of fingers? The latter is the only one that is Bump Style.
 

jblizzle

Mod Squad
TFP Expert
LifeTime Supporter
May 19, 2010
43,256
Tucson, AZ
That is the most common design I think. Try the experiment next time you need to clean the filter: backwash like you normally would and then open it up and see what is still in there. You just get such a better starting point by tearing everything apart. I actually carefully use a pressure washer on my grids to clean them up and knock of any scale that might have built up.
 
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