Anyone still adding DE to sand filters?

Rangeball

Well-known member
May 25, 2007
785
I don't believe I've seen it mentioned here, but in the past it was discussed that one could add enough DE to a sand filter to raise the pressure by 1 psi to match the filtering capability of a dedicated DE filter but with the convenience of being able to backwash the sand (then add more DE of course).

Many that did this reported it worked really well.

Just curious if it's still working, and wanting to make others aware of the option in case it is :)
 

JasonLion

TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
37,879
Silver Spring, MD
Yes, that has been mentioned here many times. I haven't seen a sticky for it though.

There is some debate about just how much of an improvement you get by adding DE. There is some improvement, but it is unclear if it is just as good as a DE filter. My guess is that it is better than plain sand but not all the way to the level of a DE filter. Another factor under debate is the improvement you get from new sand compared to old sand and how that compares to the improvement from adding DE. New sand is better than old sand right after a backwash, but once the filter is dirty it is unclear if it still makes a difference or not. Along with that, some people say adding DE is the same as having a dirty filter, just quicker, others say adding DE is better.
 

Buggsw

LifeTime Supporter
Apr 22, 2007
925
Arizona
JasonLion said:
Yes, that has been mentioned here many times. I haven't seen a sticky for it though.

There is some debate about just how much of an improvement you get by adding DE. There is some improvement, but it is unclear if it is just as good as a DE filter. My guess is that it is better than plain sand but not all the way to the level of a DE filter. Another factor under debate is the improvement you get from new sand compared to old sand and how that compares to the improvement from adding DE. New sand is better than old sand right after a backwash, but once the filter is dirty it is unclear if it still makes a difference or not. Along with that, some people say adding DE is the same as having a dirty filter, just quicker, others say adding DE is better.
...and I say, if you are in the market for a filter and are thinking, hey I'll add DE to my sand filter every week- why not just get a DE filter? :) Just kidding. I really love my new sand filter with ZeoBest in it. My former filter was a DE - which did a great job for a long time, but I really like NOT having to deal with DE powder anymore.
 

brittmer

Active member
Apr 25, 2007
38
Iowa
I add DE to my sand filter and it really helps getting the really small "floaters" that I would see in front of the light. I hardley see them anymore since adding DE.
Bruce
 

DavidD

Well-known member
Mar 29, 2007
91
brittmer said:
I add DE to my sand filter and it really helps getting the really small "floaters" that I would see in front of the light. I hardley see them anymore since adding DE.
Bruce
I had a D.E. filter up until 6 weeks ago when I sold the house. The new house had a Sand Filter already running and I noticed the same thing at night when the light was on. I remember the discussion (started by Carl D if I recall) at the "PoolForum" and thought I'd give it a try. By-golly it worked, no more "dust" floating around! :eek:

Dave
 

Buggsw

LifeTime Supporter
Apr 22, 2007
925
Arizona
Rangeball said:
Buggs, how do you find the filtering clarity with the zeobest?

How low in microns does it go?
The ZeoBest clarity is terrific. It filters down to 3 microns. I'm telling you, my water is beautiful.
 

matt4x4

Well-known member
Apr 2, 2007
312
Zeobrite and DE

My sand filter runs Zeobrite (the original zeo anything) i believe it's also 3 microns, but what I do find is the very fine dirt just filters out MUCH faster with a coating of DE than just using your filter media.
I tend to only use it if I've had to kill off algae or when I first start my pool up in the spring (I don't cover it all winter and get lots of fine dust collecting).
Cleaning up after algae can be sped up approximately 2 times by adding DE.
I have't added DE all season since startup, and my pool is so clear right now you could read the writing on a penny lying at the bottom - I know you're all going to give me heck now for adding copper to my water!!!! :)
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,863
Sebring, Florida
Okay, Okay,

I'm gonna' try it again, you rascals. I've ditched my skepticism and am off to buy some DE.

If this doesn't work, I'll hunt you down like dogs!!

Seriously, it is encouraging to hear some first-hand evidence. Most of what's been posted on this subject has been hearsay. I'll give it a shot and post my impressions.

I must say up front. however, my water is pretty doggone clean already.
 

duraleigh

Admin
Mod Squad
TFP Expert
Platinum Supporter
LifeTime Supporter
In The Industry
Apr 1, 2007
32,863
Sebring, Florida
Back home with the DE in my possession. Headed out of town so don't think I can get it in 'til Monday.

Rangeball, I have no clue. I did this about 3 years ago and can't remember how much I put in. I was careless, however, and didn't measure closely the pressure rise like I will this time. Four punds or so wouldn't surprise me but I hate to speculate....I'll post it up.
 
G

Guest

Sorry to burst the bubble of all you zeolite users. While true that zeolite does have 'pores' of extremely small size water is going to take the path of least resistance which will be BETWEEN the individual grains and not through them. The pores might help some dirt particles to adhere to them since it's the edges of a sand grain that catch the dirt and sand grains have a smooth surface compared to zeolite (Thisis why new sand filters better than 'polished off' sand from erosion of water flowing over it. The edges are polished off! Realize that high rate sand filters are also used in large aquariums and ponds [and are, in fact identical to the ones used in pools and are made by the same manufacurers--do you think it's cooncidence that Pentair has a whole division called Pentair Aquatics and that the Rainbow Lifeguard brand initially started as an aquirium filtration system when it was owned by Rainbow Plastics?] and that these present greater challange to filter since we are dealing with a 'living' system that prouduces much more debris that must be filtered out. When flltering ability is decreased over time then the remedy is to replace the sand! Common practice in aquaculture!) but, getting back to zeolite after digressing about sand, the water is going to flow basically around the grains and the grain size of zeolite is not as uniform as that of sand. In fact many of the grains are several times larger than sand grains. The larger the grain size the less the filtraton. Smaller grain size will give a higher level of filtration. Mixed grain size will filter as well as the marjority larger particles.
Zeolite cannot come close to achieving the filtration of DE (or even a cartridge for that matter, which comes very close to DE in filtering ability!) It might marginally filter better than sand because of the pores but the mixed grain size is a detirment to filtering ability so I suspect it's pretty much a 'break even' deal. The ammonia scavaging abilities are vastly overrated for pools (although it's used as a freshwater aquarium filter medium for this reason, not for it's ability to filter beter than sand!) Adding DE to a sand filter will improve filtration but it does not filter as well as DE. What you are doing is filling the spaces between the grains and making them smaller so smaller particles get caught. A slightly dirty filter does the same thing so you are, in effect, dirtying the flter! It is a given that a sligtly dirty filter will always filter better than a clean one! If the filter gets too dirty then you reduce the water flow and filtration efficiency drops (and your pressure rises as a result!)
 

matt4x4

Well-known member
Apr 2, 2007
312
zoeolite...

Thanks waterbear, that would explain why I can clean my pool up much faster after and algae breakout because the DE will coat my medium, essentially blocking the openings and hterefore catching much more dirt the first time water passes through (since the dirt is now caught on top of the DE).
Where, if I don't put DE in, I can actually watch the dirt come back out my return if I vac one of those dark spots on the bottom of the pool, you can see it blow out about 15 seconds later - the time it takes for the water to make it thorugh the system.

What I don't get is that when I add the DE to the filter, I have watched the return closely, and I don't get a DE puff coming out as I would with the dead algae - this tells me that likely, 80-90% of the DE is getting caught by the zeobrite unlike the dirt which seems to have 70% of it come back out.
I Guess the particle size of DE is larger than the particle size of the dirt....