DE vs. Sand Filter - Which One??

May 28, 2008
Its time to replace the filter on my 20x40 inground pool. Right now we have a Nautaulis DE filter. I have talked with several pool companies to get estimates and most are recommending to stick with DE (Hayward 48). However some are saying why don't you switch to Sand - less maintenance, etc. Other pool companies are telling me we probably would not be happy with the clarity of the pool - something about microns (don't even know if I would know what a micron looks like). While a Sand filter is cheaper, its not about the money - its about getting the best filter possible - less maintenance is a bonus, but if it means a cloudier pool, then I'll do some work. Can anyone shed some light on this for me? Thanks!


Mod Squad
TFP Expert
Apr 4, 2007
SW Indiana
A DE filter can filter smaller particles. I suspect that local conditions may play a role in whether that's a big advantage or not. I live in the country and get a lot of dust, but my sand filter keeps the water clear enough that I can clearly see the brand name stamped on my drain cover at the bottom of the pool. People who live in areas with different soil types might see the need for the DE, but I don't.

IMO, the big advantage of sand filters is they can deal with really dirty water much better that any other type. A DE or cartridge filter may need cleaning every half hour in an algae bloom, because they are so good at filtering.


Well-known member
May 10, 2007
Mantua, NJ
A micron is a measurement equal to approximately 1/25000 in.,,very small. A good size chart is on the pleated furnance filters for you home's heater.

A sand filter will catch down to around 20 microns while a DE filter will catch around 3-5 microns. Here is a comparison to the size difference of microns with coins. If the pool is filled with coins instead of water (who hasn't called it a money pit?), the DE will catch the quarters, nickels, and dimes. While the sand will catch the quarters but send the nickels and dimes right back to the pool.

You usually can only see the difference if you turn on the pool light at night. All of the 6-20 microns, show themselves :wink: .

The DE will give you the best clarity in your pool. However, I am very happy with my sand filter.


Well-known member
Apr 22, 2008
Central Texas
Some people add a small amount of DE to their sand filter after each backwash. They say that it helps the sand capture finer particles.

I have a DE filter and my water stays sparkling clear, like bottled water. 8)


LifeTime Supporter
Sep 13, 2007
New Bern NC
I found a site that discusses filters which may be helpful:

(I didn't know that DE was Diatomaceous Earth (D.E.))

I'm still looking around here but the question I'm trying to answer is what (if anything) I need to add to my sand filter to keep it operating at its peak ? Seems like ther are some additives to add once or twice a year so I suppose I'm looking for some guidance on what's best etc.



TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
Some people add a little DE to their sand filter after each backwash. Other than that you don't need anything. There is rarely any point to using any of the sand filter "cleaners" or "re-vitalizers" that are sold. Every two or three years you should open up the filter and clean up the sand, remove any debris and make sure the sand isn't clumping up. If there are clumps break them up and rinse the sand gently by pushing a slowly running garden hose very gently into the sand.


TFP Expert
Platinum Supporter
LifeTime Supporter
May 7, 2007
Silver Spring, MD
To add DE to a sand filter you first need to figure out how much to add. Note the starting filter pressure. Mix 1/4 cup of DE with water in a bucket and add that slowly to the skimmer (remove the skimmer sock first if you have one). Wait five minutes and then check the filter pressure. Repeat the process until the filter pressure has gone up 1 psi. Once you know how much to use, you can add that amount all at once (premixed in a bucket of water).


TFP Expert
LifeTime Supporter
Apr 17, 2007
I love my DE and don't mind giving a little maintenance or bump.

I even treat my shrubery with DE to kill the bugs that infested my rose of sharon last month. :goodjob:
May 27, 2007
Another DE "con" (the one that pursuaded me to against purchasing) is in some municipalities, it has special disposal regulations. THere aren't any regulations currently but, living in a very populous area, that could very well change.