DE in a sand filter???

I was reading a post and it said to put about a 1/3 cup in the skimmer and see if the pressure rises. IF not, add a little more. Is it OK to use DE to help out a sand filter??

Absolutely. Several of us here on the forum use a little bit of DE in our sand filters to help filter out the very small particles the sand filter just won't get. You do have to re-add each time you backwash though. Only add enough to get a 1 pound pressure rise. It generally takes 15-20 minutes for the full pressure effect to register on the gauge, so wait a while before adding more. The first time I added DE to my sand filter I added it through the skimmer then ran over and checked the pressure gauge...added more...and again...about a half hour later my pressure was up by about 20 pounds. Needless to say, I backwashed to get the excess DE out and learned my lesson on waiting!

Two questions about this subject. What is DE? What is the proper pressure for a hayword pump (1/12 hp) and 100 lb. sand filter system. Should the gauge read differat pressures when using the skimmer vs. the bottom drain? I have a 27' AG with bottom drain. These are things I have noticed but never really gave it much thought.

Your "normal" pressure is going to depend on too many factors to give you an exact number. Whatever your pressure is when you're in filter mode right after you backwash is your starting reference point.

DE is diatomaceous earth, which is a white powdery substance...it's a type of filter medium with a special filter, but many of us on this forum put a little bit in our sand filters to help with the filtration of the tiny particles a sand filter just won't get.

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. When re-filling the filter you only use half as much media. 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.

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Originally Posted by gwrace1

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. When re-filling the filter you only use half as much media. 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.

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Have you TRIED the DE-in-the-Sand method? I have no experience with Zeolite but I gather it's primarily an ammonia remover (I could be wrong).

Or maybe it puts ammonia IN your water--something that I think is VERY bad to mix with chlorine. Remember: I know little about Zeolite.

Surely there is NO way that Zeolite is cheaper than sand and DE--is there?

Backwashing every 2 weeks (about my average) is not what I consider an arduous task. If I ever run a hard pipe into the storm sewer it will be even easier--I won't even have to roll out and roll up the B/W hose--just flip a lever and watch the sight glass....

Still, do you have DIRECT experience that Zeolite works better than DE in Sand? Or are you just guessing because Zeolite has done well for you?

My water is sparkling clear too--even at night with the lights on--and it wasn't before I started using Poconos's DE trick. It was clear, but not sparkling.

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Originally Posted by gwrace1

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.

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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!

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.

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

Ok, OK, OK!!
I OFFICIALLY APOLOGIZE! :(

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

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