Adding DE to a Sand Filter - how effective is it?

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B

baudilus

Well-known member
Jun 23, 2009
156
Toms River, NJ
I am interested in doing this as I saw the how-to section in the Pool School. A quick search yielded some results that suggested some people have had success, but there may have been other factors.

What I would like to know is if anyone without other problem factors (such as poor circulation, poor water maintenance) has had any success with this.

As I've said in other posts, I have yet to have a trouble-free season, but I have at times had the water so sparkling clear that you could count the little dots on the liner. Of course, these clear times only lasted a few days or a week (due to my poor maintenance), but even then, there was always this thin film of dirt and other fine particulates that got stirred up during pool activity, and refused to be filtered - they would naturally migrate in large clumps in dead spots of the pool and I would set the vacuum down right on top of them, and watched the returns as they just came right back out into the water.

Shouldn't the DE help in such a situation, where my sand is definitely not channeled?

On a side note, I have pretty fantastic circulation for the irregular shape of my pool (only two dead spots where particles congregate outside of the swim-out and steps), a SWG supplemented with an automatic feeder, a paramount "turnover system" that cycles the wall returns off and two floor returns on every 5 minutes, and two drains at the bottom of the deep end.
 
To answer your question, it is effective/helpful. We are talking 1-2 cups so the expense seems small.
As Pool School mentions: “DE particles are microscopic and have many sharp edges, trapping fine dirt particles that would otherwise be able to get through the sand.”

Perhaps your question is "is it noticable?"
 
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In further reading, I have a concern - my local pool store sells a large quantity as their lowest available increment and I'd hate to have such a large quantity of a carcinogen sitting around since $20 worth of DE will last me 3 or 4 years.

Secondly, my pool company never plumbed by waste port to the sewer, instead attaching a hose to it and running it out back to the woods. When I backwash, all of the DE will come out and end up in the woods behind my house!

I see there is a biodegradable "green" option called Zeofiber or something - it's cellulose based, and pretty much the same price for a much smaller amount.

1. Has anyone ever used this media before? Any comments on effectiveness?
2. Would the adding procedure be the same (wait for a 1 lb rise in pressure)?
 
I've used DE in the past and still have a large box half full in the garage. My experience is that using it when the pool was slightly turbid resulted in having to backwash every day and sometimes twice a day. I could not see any real benefit in terms of clearing the water up. The pressure drop across the filter would rise quickly which reduced the flow so less water was filtered. It got to be such a hassle that I quit using it. What helped most was vacuuming the settled out particles to waste instead of sending them to the filter.

What completely cured the problem was testing and keeping the chemical concentrations where they should be particularly the bleach/CYA ratio. I did not have an algae problem all last year. The water stayed crystal clear and I only had to backwash once every six weeks or so. I no longer have those clumps of settled out particles that were stirred up by the cleaner that cause the water to look less than sparkling clear. The best part was I spent much less time and money on the pool than ever before.
 
I used the biodegradable "Fiberclear" for years in my DE filter. I have some on hand & I think I'll use it in my new sand filter.
But now that I think about it, biodegradeable will not last as long as the traditional DE. True or not?

If true, I'll probably forget about adding the biodegradeable & go find a neighor & ask if I can buy 3-4 cups of DE.

FWIW, I washed my DE filters w that biodegradeable in my grass & in a few weeks it was absent.

You asked: " Would the adding procedure be the same (wait for a 1 lb rise in pressure)?"
I don't see why not.
My real question, two of is asking really, if biodegradeable will not last as long as the traditional DE are you better off adding DE rather than biodegradeable to a sand filter? Sure the biod will work for a while, but ultimately it is absent, compared to DE which many users claim works great in a sand filter.
 
I used a vacuum hose that has a fitting on one end made to seal over the skimmer inlet and the other end attaches to a vacuum brush. The brush end connects to the extension pole that you use for brushing down the sides or picking stuff off the surface. The main pool pump supplies the suction and the multi-port valve is set to waste. You can buy the vacuum hose and brush at any pool store.
 
DE filter media can be added to a sand filter to help temporarily improve the filter's overall quality. The amount of DE depends on the diameter of the sand tank, you may want to check with a local dealer to see exactly what they recommend, as it may be different depending on the DE. However, this is a VERY temporary solution. It is highly recommended for use in any pool with a sand filter that is having water clarity problems. Because sand filters don't have the micron filtration that DE does, adding the DE gives the sand filters a 'supercharge'. The DE needs to be added to a skimmer, and will basically sit on the top of the sand, creating a 'prefilter' for all of the debris that is coming in. Because of this, your particle pickup size goes from around 15 micron down to 2 or 3 micron, so your filter is going to build up pressure must faster than you are used to. As long as you are backwashing at the appropriate PSI, you cannot cause any damage to your equipment, and will see much better results. Hope that helps =]
 
FWIW, I have just added that biodegradable DE alternative called FiberClear, yes its fine in a sand filter- says so on the package.
Brand new sand, then opened pool so most of the debris, then 6 days later added the DE. It takes 11 cups to raise 1 psi ! I added ¼ cup at a time, 44 x ¼ cups= 11 cups, & really it went about ¾ psi but I stopped because Pool School said “usually 1-2 cups”.
24 hours later had to backwash. Took 13 cups to raise 1 psi !
My old DE filter was 48SF & it took 12 cups to coat all those grids. And now I am just trying to coat the top of my sand. What gives? If it doesn’t take just 1-2 cups, I will probably just reserve this ole add-DE-to-sand-filter trick for some urgent clarity need.
Or do you guys think over time it will may require less DE?

Thanks
 

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Edited to delete misinformation

Here is the recent history, perhaps we can learn something.
Per the above post:
Brand new sand in brand new filter & gauge is behaving consistently & normally as far as I can tell, then opened pool so most of the debris is gone, then 6 days later added FiberClear ( "boidegradeable replaces DE"). It took 11 cups to raise 1 psi ! Really it went about ¾ psi but I stopped because Pool School said “usually 1-2 cups”.

1- 24 hours later had to backwash. Took 13 cups to raise 1 psi !
Total of 24 cups.
No visible debris in clear unbalance (CC >0.5 at times so shocking) water, heavy pollens but no leaves etc

I’d conclude: when adding “DE alternative” to a sand filter, don’t exceed 2 cups of “DE alternative” per backwash even though the pressure may not rise as expected. This is a single report that perhaps the pressure doesn’t rise for several hours when using “DE alternative”. Furthermore, the filter pressure of a clean debris-free balanced pool behaves differently of course than one that is not.

If I was to do this over again, I'd stop at 2 cups. Of course if I saw the 1 psi increase sooner than 2 cups I'd stop there

I have read elsewhere on TFP that other sand filters pressure see no rise until the last 1-3 hours before a backwash is needed then it kind of all happens at once in the final few hours. This is how my filter behaved both before & after the “DE alternative” was added.
 
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I chose to buy a small bag of the biodegradable DE alternative, and the instructions on the bag are different from the DE instructions.

I chose this because I was not too keen on having a pile of DE in the woods behind my house that could become airborne once dried out. I will post my results in few weeks once my pool is open and cleaned. I plan to let the sand work for a while on the bigger stuff, and then add the fiberclear to work on the smaller stuff.
 
Update: my psi hasn’t increased a bit in weeks, it is at the lowest/clean psi, same psi as before I added any DE alternative, I’m assuming I backwashed it all out.
I added 2 cups of the same stuff , no increase in the psi in over 2 days, that is all I’ll be adding.
 
I have a question regarding DE and other "filtering alternatives".

When I purchased this house the sand had been replaced, there were still buckets of the stuff in the garage so I know it was done. When I examine the sand it is nothing more than regular "play sand" they sell at the local "Rona/Revy", I was expecting some sort of special fine sand such as indoor "play sand" which is all fine particles not a mixture of coarse and fine sand.

Is this correct?

Next I was thinking if this is all it is why not use some type of silica like that used in sandblasting, its much finer quality and has very sharp edges. Has anyone tried this type of "sand" for filtering?

It would seem to me that "edge" sharpness is not the only criteria for DE selection as this micrograh shows;

http://www.corbisimages.com/Enlargement/42-18707848.html

Looks to me like DE is more a microporous element than a "sharp" media?
 
4JawChuck said:
I have a question regarding DE and other "filtering alternatives".

When I purchased this house the sand had been replaced, there were still buckets of the stuff in the garage so I know it was done. When I examine the sand it is nothing more than regular "play sand" they sell at the local "Rona/Revy", I was expecting some sort of special fine sand such as indoor "play sand" which is all fine particles not a mixture of coarse and fine sand.

Is this correct?
Pool filter sand is a special sand, mine call sfor: #20 standard silica sand with a uniformity coefficient of 1.75 or less.

Next I was thinking if this is all it is why not use some type of silica like that used in sandblasting, its much finer quality and has very sharp edges. Has anyone tried this type of "sand" for filtering?
I haven't, but that is kind of cool. Let's see what the experts say

It would seem to me that "edge" sharpness is not the only criteria for DE selection as this micrograh shows;

http://www.corbisimages.com/Enlargement/42-18707848.html

Looks to me like DE is more a microporous element than a "sharp" media?
Click to expand...

DE filters better than sand. I've had both filters. Sand is way less work
 
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