DE in a sand filter???

[Madty]

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??

[Sherra]

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!

[conductor500]

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.

[Sherra]

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.

[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.

[CarlD]

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.

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.

[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!:mad:

(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.:D

[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.

[gerri]

This morning my pool water is clearer than it's ever been. If not for the metal stains it would be just perfect! :D

[cschnurr]

Went to the 3 pool stores to pick up DE. They didn't have any, but had an "equivalent" thats supposedly better than DE.

I tried it on the weekend, waiting only about 5 minutes, before reading the pressure gauge. Pressure rose very little, so I put in another cup, 3 in total.

Later in evening, checked pressure gauge and it was up 8 lbs.
So I had to backwash it away and start over.

How long should to wait for the pressure to increase?

[medvampire]

cschnurr

It takes mine about 20 to 30 minutes to raise. I get a 2 to 3 psi per 1 and a quarter cups. The de does work but I have noted it takes a few days to really notice the diffrence.
Steve

[Poconos]

cschnurr...Carl,
What was the stuff they sold that is supposed to be better than DE? Just curious. All I know is the approximate time for the presssure to stabilize when adding DE. The amount you add to get the target 1 psi rise is also very dependant on the filter size.
Al

[CarlD]

It's this new stuff that folks have written about that's some sort of DE substitute that's less dangerous to breathe. Some sort of fibrous stuff. I have NO idea how it works, or how well it works, but it's supposed to be OK to use with a cart filter, unlike real DE.

[waterbear]

There are two kinds of DE replacements...One is cellulose fiber and the other is perlite, a type of volcanic rock. I have no info on the filtering ability of either as to how small they will filter. I know the cellulose one can be used with cartridge filters since it doesn't clog the reemay polyester filter material. The perlite is still a silceous (glass) rock so it still might be dangerous to inhale. don't really know.

[cschnurr]

The stuff I was sold sounds like the cellulose material Waterbear mentioned.

It had a generic name like "DE filter additive". Instructions stated for DE filters or sand filter additive, and also stated it was 5x the efficiency of DE. It was off-white in colour and extremely lightweight.

It was $13 Cdn, for about 3-4 cups.

My question to the pool store where I purchased it was if it is 5x DE, how can so little of it spread entirely across the filter. She didn't know.

[mohawk]

Not to sound to ignorant but when you put the DE in the skimmer what setting is the filter on? If it is on filtering the DE would be pushed out into the pool. Do you leave it on backwash? For how long?

[Rangeball]

Not to sound to ignorant but when you put the DE in the skimmer what setting is the filter on? If it is on filtering the DE would be pushed out into the pool.

You leave it set on filter. It catches at the top of the sand and does not return to the pool unless you have a filter problem.


Do you leave it on backwash? For how long?

You only backwash when you want to clean your filter. If you backwash after you've added DE, it rinses out and you have to re-add it.

[gwrace1]

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.

I recommend it because it has worked so well for us. We had no water available to us other than from a very hard water iron rich well. We wanted the maximum filtration we could get from the filter with the least amount of maintanance. We got that with the sand filter and Zeolite.

We knew the pool was going to get it's share of air borne debris from the various trees in the area. We also wanted to put as little effort as possible into pool maint. We got that from the SWG, Poolskim, Pool Rover, sand filter with Zeolite. I've had to backwash the filter one time since the pool was installed in early March.

I don't know that you can justify the cost over DE in sand. However here are some things to consider.
1. You only use have as much Zeolite as you would sand.
2. You backwash much less frequently which conserves water and chemicals and is easier on the enviornment.
3. Zeolite is a natural bio-degradable medium so can be disposed of safely which includes using it in your garden.
4. The reduced labor and maint. hours should add up to some value.
5. Zeolite is renewable. When the filtration qualities diminish you recharge the medium with a salt solution. It is "supposed" to outlast sand many times over. Our neighbor has a never ending sand pile as he replaces it every year (softswim user).
6. I don't think a cost of $40.00 for a 50lb bag is all that expensive comparied to the per ounce per pound cost of other pool chemical products. We needed 175 lbs for a total cost of $160.00 with some left over.

Just some things to consider.

[gwrace1]

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!

It's funny how whenever someone posts information about a product that is somewhat out of the norm the naysayers come out in great numbers. I'm speaking from actual experience in using the product.

Do the research & look at the test results. I think you will find that indeed Zeolite does provide equal to or better filtration properties than DE. It's less maint and is easier on the envionrment.

I have large aquariums but your talking about two completely different environments with different pump and filter equipment exposed to different elements under different conditions. Lets compare apples to apples.

All I can tell you is I've had no iron staining, algea or any other water treatment issues. I love my almost maint free pool.

[mohawk]

Now I figured it out. The way my pool was plumbed was wrong. I didn't think it looked right last night so I called the store and they said it was reversed. I have water coming out of my skimmer and water going in at the eye. The installer is on his way back to fix it. Duh-you'd think they'd know how to plumb the pump when this is all they do in the summer. Denise

[Rangeball]

If you add DE before they get there, add it through the eye :)

[waterbear]

I recommend it because it has worked so well for us. We had no water available to us other than from a very hard water iron rich well.
Zeolite can remove heavy metals (including calcium and iron) from the water in much the same way it removes ammonia (and in fact is sometimes used in water softener units as the ion exhange resin) but it is not nearly as effective as other water softening resins and if the concentrations are high it will require regeneration once it's capacity has been reached ...see below about regeneration of zeolite. Also water softeners are regenerated with the brine solution ususally at least a few times a week so this ability will quickly diminish!
We wanted the maximum filtration we could get from the filter with the least amount of maintanance. We got that with the sand filter and Zeolite.

We knew the pool was going to get it's share of air borne debris from the various trees in the area. We also wanted to put as little effort as possible into pool maint. We got that from the SWG, Poolskim, Pool Rover, sand filter with Zeolite. I've had to backwash the filter one time since the pool was installed in early March.

I don't know that you can justify the cost over DE in sand. However here are some things to consider.
1. You only use have as much Zeolite as you would sand.
That is by weight, not by volume. It weighs about half as much as sand. The price per pound is much higher than sand. A 50 lb bag of sand sells for about $6 so 6 bags would be 300 lbs and costs $36. A 150 lb bag of Zeobrite (equivalent to 300lbs of sand) sells for about $75 dollars...more than double the price for the same amount needed!
2. You backwash much less frequently which conserves water and chemicals and is easier on the enviornment.
This is probably true since the rough surface of zeolite can trap more dirt than the smooth surface of sand. One plus for zeolite. However the grains are actually up to 3X larger than sand grains (up to 1.5 mm while sand is about .5 mm) and that will reduce the mechanical filtering ability so you might only be breaking even here.
3. Zeolite is a natural bio-degradable medium so can be disposed of safely which includes using it in your garden.
Last time I checked DE was also a natural medium. Zeolite does not biodegrade. It is a mined mineral and is a hydrated (containing water) alumino-silicate oxide (contains both aluminum and silicon). Sand is silicon dioxide (silica). DE is the fossilized shells of prehistoric freshwater and marine organisms and is primaily silicon dioxide(silica) with a smaller amount of aluminum dioxide and other minerals present. All three are mined. Non of them biodegrade. All of them can be mixed into your garden but all they are basically a form of sand (silica).
4. The reduced labor and maint. hours should add up to some value.
remains to be seen. With the necessity of 'recharging' the zeolite yearly (for chlorine pools) with an acidic brine solution it might be more labor than sand.
5. Zeolite is renewable. When the filtration qualities diminish you recharge the medium with a salt solution.
Zeolites main advantage is the ability to adsorb (not absorb!) ammonia compounds. It has been used for aquarium filtraton for this reason for many years. It acts like an ion exchange resin in your water softener and is functioning as a chemical and not mechanical filter medium in this respect by trapping ammonium ions. When it cannot adsorb any more it can be regenerated with an acidic brine solution (concentrated salt solution and acid). As far as cleaning it of particulate matter (mechanical filtration) that is what backwashing does so it is no different than sand here. Plus you have the added step of 'recharging it yearly and have the brine solution to dispose of....good way to kill the grass!
It is "supposed" to outlast sand many times over. Our neighbor has a never ending sand pile as he replaces it every year (softswim user).
Can't compare biguind (SoftSwim) to chlorine here. Even on the Zeobrite website they recommend cleaning the zeolite medium MONTHY with the above cleaning solution when using bigiunide. The makers of the various biguinde systems (Baquacil, SoftSwim, Revacil) also recommend monthy cleaning of sand when used with their systems and yearly reppplacement. Seems like it's exactly the same. It will still probably require yearly replacement (or perhaps more often) just like sand since since biguinide gunks up and ruins filter material and the 'pores in the zeolite will certainly get gunked up fast.
6. I don't think a cost of $40.00 for a 50lb bag is all that expensive comparied to the per ounce per pound cost of other pool chemical products.
We needed 175 lbs for a total cost of $160.00 with some left over.
Sand at $6/50 lb bag would have cost you $24. Even if you paid a premium price of $12/50 lb bag of sand that is still less than $50 total! Think of all the bleach you could have bought with the left over $100-$125 dollars!

Just some things to consider. Just a few more things to consider!

[brent.roberts]

Comments have been made in this thread that you can reduce the number of times backwashing is required.

Think about this. Your systems starts up and your skimmer collects a handfull of dead and drowning insects. Earthworms fall into the pool and settle out on the bottom and get sucked into the bottom drain. A lb. of pollen drifts onto the surface and is sucked into the skimmer. A bunch of swimmers jump in an dead skin sloughs off. Some feces are washed out the swim trunks. Hair, grass etc.
You all know the routine. ( or should )

So it goes into you filter and is filtered out. Out of what ? Out of sight and nothing more.
And that's where it ends until you flush it out with a backwash. All that junk from March, ... it's now July, is still in your pool water. In fact much of it is force fed pool water while ever the pump is running.

4 month old dead rotting earthworms ... still in the pool water. Just out of sight.

Now if you're real good about your chlorine and CC levels, it is eventually going to be oxodized. But any bit of a slip up in your routine and you have be saving up all this stuff to make a biological time bomb.

I think it is foolhardy to leave that junk in you system and think you are smart by saving 5 minutes to backwash and a hundred gallons of water.

Just my opinion. Comments and critique invited.

[gerri]

I'm also a big believer in backwashing. I don't mind having to re-add the DE or replace some water and sequestering agent. I just think it's a much cleaner pool when the filter material is as clean as it can be. I don't have a bottom drain though so my worms and stuff get emptied when I vac.

[sevver]

I backwash every time I vacuum. Before I do it I fill the pool til it is a bit high then vac, then backwash. I have an 18' pool, and it gets low when I BW if I don't fill it up first sometimes.

[CarlD]

If your pool is clear, your FC and CC are fine, you don't keep having drastic chlorine drops, then the detritus in your filter is past rotting and you needn't worry about it.
Backwash when the pressure goes up. If it's once a week or once a month, so be it.

However, if you DO get an infested sand filter (very rare, but I know someone who had one) it's cheaper and easier to just replace the sand. At $5 for 50 # it's not pricey.

[The Raddish]

Here's a question. My new Pentair Dynamo 3/4 Hp two speed pump is being delivered today. I plan on running the pump on the low speed setting for about 12 hours a day (turning off at night), and only using the high speed setting for vacuuming, running the fountain when we have guests, and during high bather load.

So, if/when I add DE to the filter, do I add to 1lb increase on the low setting, or the high setting? I'm assuming that I add to a 1lb increase on the low setting, but wouldn't that equate to more than 1lb when it is on high?

[CarlD]

Absolutely add the DE when running on high. Do not do it on low. The pressure may well be too high if you add it on low.

I have a two speed and use the DE and always add it when the filter's on high--it's easy because I backwash on high and I add the DE right after I backwash.

[The Raddish]

Thanks Carl. That's the answer I was expecting. :)

[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. :)

[brent.roberts]

If your pool is clear, your FC and CC are fine, you don't keep having drastic chlorine drops, then the detritus in your filter is past rotting and you needn't worry about it.
Backwash when the pressure goes up. If it's once a week or once a month, so be it.

However, if you DO get an infested sand filter (very rare, but I know someone who had one) it's cheaper and easier to just replace the sand. At $5 for 50 # it's not pricey.


Carl
I'm not sure the idea that the stuff in the filter is past rotting is valid. Last summer I got a new DE filter. The dealer did not supply the multiport valve so I could not backwash. The instructions, as usual said to backwash after noting a pressure rise. After 2 month my pressure only went up 1 1/2 lbs so according to the bood, it didn't need a backwash. But I decided to open it up and hose it off anyway.

I was astonished at the amount of cr@p on the DE. The smell was horrendous. The pool water still showed negligable CC and the FC was held pretty steady at about 5 PPM so it looked OK externally.
But inside YEAUKKKKK.

Next cycle I opened it up again after 1 month. Virutually the same mess. The chlorine does not really break down the stuff in the filter the way I expected it to. Now I clean the filter every two weeks. The blankety blank dealer still has not send the backwash vales so I still do it the hard way. But I won't every leave it for a month or two.

Try taking a 5 gallon pail and catch some of the backwash water about a minute after the flow is reversed. Pretty disgusting.

[waterbear]

Carl
I'm not sure the idea that the stuff in the filter is past rotting is valid. Last summer I got a new DE filter. The dealer did not supply the multiport valve so I could not backwash. The instructions, as usual said to backwash after noting a pressure rise. After 2 month my pressure only went up 1 1/2 lbs so according to the bood, it didn't need a backwash. But I decided to open it up and hose it off anyway.

I was astonished at the amount of cr@p on the DE. The smell was horrendous. The pool water still showed negligable CC and the FC was held pretty steady at about 5 PPM so it looked OK externally.
But inside YEAUKKKKK.

Next cycle I opened it up again after 1 month. Virutually the same mess. The chlorine does not really break down the stuff in the filter the way I expected it to. Now I clean the filter every two weeks. The blankety blank dealer still has not send the backwash vales so I still do it the hard way. But I won't every leave it for a month or two.

Try taking a 5 gallon pail and catch some of the backwash water about a minute after the flow is reversed. Pretty disgusting.
You are actually better off breaking the filter down instead of backwashing it. I have posted my reasoning for it in other threads so I will not go thru it again but in a nutshell you really don't know how much DE is washed out so you really don't know how much DE to add. Also, backwashing forces dirty water backwards through the grids. You know that if you run a DE filter, even for a short time, without DE the grids can get clogged. IMHO, the same can happen when the water goes through them backwards.