DE in a sand filter???

[waterbear]

In my opinion you'd be better off refilling the filter with Zeolite. Has filtration properties similar or better than DE down to 2 microns.
Zeolite has pores in it of about 3 microns in size but that doesn't mean it will filter that small since the grain size is about the same as sand. Basic physics...water will take the path of least resistance which will be AROUND the grains...not through them. You might get a slightly better filtering ability because the surface of the zeolite is much rougher than sand because of these pores so there are more areas to trap dirt on the surface of the grain compared to the more smoooth surface of a sand grain...but you are not really getting micron filtration
When re-filling the filter you only use half as much media.
You are using half as much by weight but about the same volume. Zeolite weighs less than sand. The volume needed for your filter will be the same with either sand or zeolite.
Our 26" filter requires 350lbs sand but only took 175lbs of Zeolite. We've only had to backwash once in the 4 months we have been using the pool and we use it almost daily. Water is crystal clear.

Zeolite seems to be the new 'miracle product' for pools. It has been used in aquarium filtration for years, primarily for it's ammonia scavaging ablility. In aquariums it has not proven to be a better mechanical filter than sand.

Carl, the trick with DE in a sand filter has been around for a long time. I first heard about it about 20 years ago from my neighbor with a pool (I didn't own a pool back then). He learned it from his pool service guy!

[faithfulfrank]

I have heard of the "DE trick" and always meant to try it. Well, after reading this thread, I decided to try it.
I have a 30' AG pool about 20,000 gal, and a 150 lb sand filter with a 1 hp pump. Per the directions, I added sabout 1/2 a cup, waited about 30 min, then checked the pressure guage. Prior to doing this, the pressure was 16psi. It stayed there after I added the 1/2 cup.
I then added about a cup more, and 30 min later it was about 16.5 psi.
Should I add more?

this year is about my fourth year with the pool.....previous years the psi was always around 12psi after backwashing. This year when opening the pool I looked at the sand and it looked brand new, so despite what the poolstore said, I kept it. I'm told here that as long as all is well, you should not ever need to change the sand.

Anyway, could or should I add a bit more DE....?

Thanks, Frank D.

BTW, I added pics of my pool and deck in the A/G pool pic thread, if anyone in interested.

[Rangeball]

Every recommendation I've ever read said keep adding until you hit a 1 psi increase.

[CarlD]

Ok, OK, OK!!
I OFFICIALLY APOLOGIZE!

Al (Poconos) gets NO credit at all for the DE-in-the-Sand-Filter trick!

(even though he has been the Apostle for it! )

[faithfulfrank]

I added some more, and it is now 1 psi higher.
Now, I wait for the transition from clear and clean to sparkling!

Frank D.

[drband]

DE in my sand filter really works great... I just added about 1 cup total today and my pool cleared from slightly hazy to sparkling in 3-4 hours. (I had already shocked and cleaned it up... there was just some fine stuff suspended in the water that the sand filter would not catch.) I'm sold on this "trick." Thanks for all the posts, questions, and info.

[gerri]

I added 1/3 cup to my filter tonight. I hope i wake up to sparkling water. My dad uses DE in his aquarium filters and swears by it. He calls it "water polisher". He told me to mix the DE in a little bit of water before adding it so it doesn't gum up, so I did. When I poured it in the skimmer there was a little grit in the bottom of my cup but I just added a little more water and swished it around and the cup rinsed clean. I will post results tomorrow.

It won't be as great as it could be though as I am battling metal stains right now. I'm doing an asorbic acid treatment on Wednesday though in hopes of having the sparkling clean looking pool.

[AndieP]

I went to Lowes today to get some DE for our filter and all they had was a 25pound bag....it was cheap $13... but now I'm wondering how well it keeps. Will it keep through the winter until next summer since I'm sure I won't use even 1/4 of it the rest of this summer? How should it be stored? Should I take it back and keep searching for a small size?

[drband]

Should keep indefinitely... just keep it dry so it won't clump up.

[gerri]

DE is actually little microscopic skeletons so it's good basically forever.