How much DE to add to a clean filter?

[BrownDogs]

How much DE to add to a clean filter?

I have just removed and deep cleaned my DE filter. I’m wondering how much DE to add? And if I added enough? It is a 48 sq. ft. Titan Vertical Grid Filter.

When I did it the last time, I felt it was not full of enough DE. I put what I thought was 5 lbs. but I did not weigh it. When vacuuming the pool when it was really dirty, there was small 0.25 - 0.5” leaf/plant debris coming out of the return and landing back on the pool bottom. So I thought it may not have enough DE. And I just noticed there is a small 0.75” tear of the fabric in one of the grids. Most, if not all, of the grids have a few broken ribs. I’m not seeing DE in the bottom of the pool.

Here’s what it looked like when I opened it up this time.

Did I not add enough DE last time? I did add the DE to a bucket and poured it into the skimmer last time. Maybe it wasn’t enough? I never did a backflush & recharge and it ran with that amount for about a year.

This time I decided to weigh the DE and again mixed it with water in a bucket before pouring it into the skimmer. It seems like it is filtering nicely after the deep clean and recharge but wonder if it has enough?

One more thing, I took note of the pressure on the gauge before adding any DE. It was 15 psi at full priming speed (3450 rpm). After adding 6.25 lbs. of DE it still was at 15 psi at full speed. Is this normal?

To summarize my questions:

• Did I not add enough DE last time based on what the picture of the grids looked like?
• Did I add enough this time? About 6.25 lbs. weighed out for a 48 sq ft grid.
• Is my 15 psi pressure before and after 6.25 lbs. DE okay? Should I expect higher psi after adding DE?

 

[ajw22]

The manual says 4.8 lbs for a 48 sq in filter. See top of page 5.

6 lbs is too much.

https://www.poolforensics.com/manuals/filters/de_titan_filter.pdf

I think you need new grids.

 

[oldprophet]

How much DE to add to a clean filter?

I have just removed and deep cleaned my DE filter. I’m wondering how much DE to add? And if I added enough? It is a 48 sq. ft. Titan Vertical Grid Filter.

When I did it the last time, I felt it was not full of enough DE. I put what I thought was 5 lbs. but I did not weigh it. When vacuuming the pool when it was really dirty, there was small 0.25 - 0.5” leaf/plant debris coming out of the return and landing back on the pool bottom. So I thought it may not have enough DE. And I just noticed there is a small 0.75” tear of the fabric in one of the grids. Most, if not all, of the grids have a few broken ribs. I’m not seeing DE in the bottom of the pool.

Here’s what it looked like when I opened it up this time.
View attachment 481319
Did I not add enough DE last time? I did add the DE to a bucket and poured it into the skimmer last time. Maybe it wasn’t enough? I never did a backflush & recharge and it ran with that amount for about a year.

This time I decided to weigh the DE and again mixed it with water in a bucket before pouring it into the skimmer. It seems like it is filtering nicely after the deep clean and recharge but wonder if it has enough?

One more thing, I took note of the pressure on the gauge before adding any DE. It was 15 psi at full priming speed (3450 rpm). After adding 6.25 lbs. of DE it still was at 15 psi at full speed. Is this normal?

To summarize my questions:

• Did I not add enough DE last time based on what the picture of the grids looked like?
• Did I add enough this time? About 6.25 lbs. weighed out for a 48 sq ft grid.
• Is my 15 psi pressure before and after 6.25 lbs. DE okay? Should I expect higher psi after adding DE?

1 lb of DE for every 10 square feet of grid space is the formula

 

[BrownDogs]

Thanks guys. I appreciate the link to the filter manual, ajw22.
I know that most of the info I have read says 1 lb. per sq. ft. and so did the old bag of DE. The new DE (box of Dicalite) says that for 50 sq. ft. to use 7.5 lbs. to precoat. I used 6.25 lbs. this time fo my 48 sq. ft. filter.

But what do you guys think of that picture of the grids? Was that not enough last time?
And what about pressure? It didn't change after adding 6.25 lbs. Should it go higher after adding DE?
I'm going to order a new replacement grid pack. Maybe the tear and broken fins are indeed causing issues. Water is looking pretty good during the SLAM.
Thanks again!

 

[JamesW]

But what do you guys think of that picture of the grids?

The turquoise color suggests copper levels are high.

 

[1poolman1]

Thanks guys. I appreciate the link to the filter manual, ajw22.
I know that most of the info I have read says 1 lb. per sq. ft. and so did the old bag of DE. The new DE (box of Dicalite) says that for 50 sq. ft. to use 7.5 lbs. to precoat. I used 6.25 lbs. this time fo my 48 sq. ft. filter.

But what do you guys think of that picture of the grids? Was that not enough last time?
And what about pressure? It didn't change after adding 6.25 lbs. Should it go higher after adding DE?
I'm going to order a new replacement grid pack. Maybe the tear and broken fins are indeed causing issues. Water is looking pretty good during the SLAM.
Thanks again!

Those grids should be replaced. In normal operation the DE should fall off the grids with the pump off, as it looks in the picture. If the grids remain coated usually the cause is oils that make the DE stick together in a paste that won't fall off nor backwash well. The proper amount of DE will coat the grids about 1/8" and all that build-up on the top and manifold won't be there.