Could my DE filter get this bad in six weeks?

Nicholas7

Member
Apr 8, 2025
11
Texas
Pool Size
12000
Surface
Plaster
Chlorine
Liquid Chlorine
I am new to pools, owned one since Feb. Pump pressure was consistently around 40psi. So I decided to clean the filter. Attached is what it looked like when I opened it up.
My pool company claim to have washed the filter in March.
My question: is could it have got that bad in six weeks?
CheersFilter_Before_Cleaning_1.jpg
 
Nick,

Really depends on what your water looks like..

Algae can clog a DE filter in hours...

A filter pressure of 40 is insane.. !!!!

The higher the pressure, the harder it is to push water through the filter..

It should be down around 10 in your case..

It is a little late to blame someone else...

Thanks,

Jim R.
 
Well it did. We don't know how much dust and dirt blows into your pool from the Texas plains.

What is your clean filter PSI?

Was there DE in the filter?

How much DE do you add after cleaning the grids?

Do you have an MPV or a slider valve?
 
Nick,

Really depends on what your water looks like..

Algae can clog a DE filter in hours...

A filter pressure of 40 is insane.. !!!!

The higher the pressure, the harder it is to push water through the filter..

It should be down around 10 in your case..

It is a little late to blame someone else...

Thanks,

Jim R.
Thanks Jim,
The water has been clear since we arrived, and fine for swimming. After the Maintenance guys put in 3lb dichlor the cya got to ~200. I changed 75% and it is now around 40.

It was all new to me - the pump had been consistently around 40 since we moved here. I am now maintining the pool by myself. Th filter was so bad I could not believe that it had happened so quickly. But then I don't know what is normal.
Since cleaning it has remained solidly on 17psi.
 
Well it did. We don't know how much dust and dirt blows into your pool from the Texas plains.

What is your clean filter PSI?

Was there DE in the filter?

How much DE do you add after cleaning the grids?

Do you have an MPV or a slider valve?
Thanks ajw,
When you say 'well it did' do you mean it is possible that a clean filter got that bad in a few weeks even though we have had no algae?

Not so much dust here, surrounded by trees and scrub.

I put in 9lb DE and the psi has remained steady at 17.

Don't know what an MPV or slider valve are.
 
When you say 'well it did' do you mean it is possible that a clean filter got that bad in a few weeks even though we have had no algae?

We don't know if you have algae.

Does your pool pass a Overnight Chlorine Loss Test?
I put in 9lb DE and the psi has remained steady at 17.

What model and size is the filter? 9 lbs sounds high.

With a clean pressure of 17 you should backwash or clean the filter when the PSI rises by 25% to 30% or around 23 PSI.

You should not let the PSI get to 30 or 40.

Don't know what an MPV or slider valve are.

 
Texas Pool Builders hate SWGs for some reason and love trichlor tab feeders.

Exclusive trichlor tab use is a disaster.

The grids are clogged with something, maybe mud, but hard to tell for sure.

1745854281406.png
 

Enjoying this content?

Support TFP with a donation.

Give Support
Nick,

You are supposed to take all the grids apart and clean them.. Then put them back together...

The first time I did that I almost cried... :mrgreen: it took me an hour to finally get them back together... It now just takes a couple of minutes..

I gave up on DE filters a long time ago.. What a pain...

I now have a large cartridge filter and clean it once a year.

Thanks,

Jim R.
 
Nick,

You are supposed to take all the grids apart and clean them.. Then put them back together...

The first time I did that I almost cried... :mrgreen: it took me an hour to finally get them back together... It now just takes a couple of minutes..

I gave up on DE filters a long time ago.. What a pain...

I now have a large cartridge filter and clean it once a year.

Thanks,

Jim R.

Wow - I couldn't even get the assembly out, never mind strip it down. I was also concerned about what brute force would do to the connecting pipe.

I will research cartridge filters.

Cheers
 
We don't know if you have algae.

Does your pool pass a Overnight Chlorine Loss Test?


What model and size is the filter? 9 lbs sounds high.

With a clean pressure of 17 you should backwash or clean the filter when the PSI rises by 25% to 30% or around 23 PSI.

You should not let the PSI get to 30 or 40.



No algae.
The filter is 72 sq ft and 9 lb DE is specified on the casing (and on line). Pressure is still 17 - point taken about back-washing.

Since changing 75% water two weeks ago I have been trying to get on top of the chemistry (using the TFP recommended pro kit) using liquid chlorine. (Previously they had used lots of tablets and dichlor)

Yesterday FC was 1.5 and CC was 0.5, cya was 40, pH was a bit high at around 8.0.
Thanks
 
Texas Pool Builders hate SWGs for some reason and love trichlor tab feeders.

Exclusive trichlor tab use is a disaster.

The grids are clogged with something, maybe mud, but hard to tell for sure.

View attachment 641265
I believe you, he had put in new tabs in addition to the 3lb dichlor - which I assume is what kicked his reported cya up from 100 to ~200.
I am using Liquid chlorine now.
 
  • Wow
Reactions: JamesW

Enjoying this content?

Support TFP with a donation.

Give Support