DE in a sand filter???

[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.

[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.

[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.

[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.