Sand Filter or Cartridge?? Which is better?

[CarlD]

I AM surprised...if you backwash your DE filter until the sight glass is clear, then you know you probably have no DE in it. So you add DE, leaving some "room" in case there is some left, until the pressure is where it's supposed to be...and you're done.

And I'm a sand filter guy.

I increase the sand filtering effectiveness several ways:
1) I have a filter clearly rated for a higher capacity than my pump.
2) I have a 2 speed pump I run on "low" most of the time--this increases the difference between the pump and filter and filter is more effective.
3) I add a cup of DE powder after I backwash, enough to raise pressure 4-5 #, no more (see Poconos) which catches more fine stuff.
4) I use "skimmer socks" in my skimmer to catch a portion of the fine stuff there.
5) I run my Dolphin overnight once a week. The Dolphin has as fine, if not finer, a filtering as a DE. It's high-flow, and runs for 8 hours as it's vacuuming, "polishing" the water.
6) I wear out-of-focus glasses so everything is fuzzy and I can't see if the water isn't perfectly clear!

[waterbear]

I AM surprised...if you backwash your DE filter until the sight glass is clear, then you know you probably have no DE in it. So you add DE, leaving some "room" in case there is some left, until the pressure is where it's supposed to be...and you're done.

In a perfect world, yes. DE can have a tendancy to "cake" (for want of a better word) on the grids and even if the sight glass looks clear it is possible for there to be quite a bit of DE left in the filter. You add your DE and leave some 'room' but the filter only lost a little of its DE powder. You have now overfilled. Might not show up on the pressure gauge at first. Do this a few times and you now have a MAJOR filter cleaning to do. This scenerio can happen and does. If you have ever had to chip away at the hardened mass of DE that can occur you certainly don't want to do it more than once!

That is why I feel it is better to tear down rather than backwash a DE. You really don't have any control of knowing how much DE is leaving the filter and therefore how much you REALLY need to put back in.
Bumping is really just being lazy, Mixing the DE with the dirt and crud collected and then redepositing it on the grids is NOT the way to give you good filtration. When the filter media is dirty it needs to be cleaned!
Like I said, just my opinion!

[KurtV]

I'm surprised no has mentioned one of the other favorites in this never-ending debate: Sand filter with zeolite filter medium. The ease of maintening a sand filter with a filtering capability that's better than a cartridge and maybe even better than DE. Can't be beat, right?

(Patiently awaiting post describing arduous zeolite "renewal" procedure that must be performed annually but that no one who actually has this system seems to worry about.)

[waterbear]

I'm surprised no has mentioned one of the other favorites in this never-ending debate: Sand filter with zeolite filter medium. The ease of maintening a sand filter with a filtering capability that's better than a cartridge and maybe even better than DE. Can't be beat, right?
If you really believe all the manufacturer's hype then PLEASE come into the pool store where I work part time and let me sell you some dual action Pace 3" tri-chlor that will keep algae from your pool and make your life simpler along with some sodium hydrogen carbonate for adjusting your TA ...it's better for your pool than baking soda! (those comments ARE 'tounge in cheek'!)
(Patiently awaiting post describing arduous zeolite "renewal" procedure that must be performed annually but that no one who actually has this system seems to worry about.)

Zeolite is great for ammonia scavaging and will probably help to keep choramines down (if you are not using a SWG) but I don't believe it's filtering abiltiy is going to be much better than sand. Yes, it is porous like DE and the pores have a small micron size but the grains are about the same as sand; and water (and the dirt in it) is going to take the 'path of least resistance' which means it will go around the zeolite grains and not through it. DE on the other hand, has a very tiny particle size and when the slurry of DE and water coats the grid, even though the coating is not that thick it is made of of layers and layers of DE the path of least resistance will be throught the porous DE which is what makes it such an excellent filter medium. Even if the water passed around the DE grain it is so tiny that the space between grains is extremely small also.
Actually,I have read through Zeobrites regeneration instructions on their website and they are really no worse than sand cleaning or cartridge soaking (which many cartridge and sand owners don't worry about either!) and is probably only a yearly procedure also. The biggest difference between zeolite and sand its that while sand is only a mechanical filter medium, zeolite is both a mechanical AND chemical filter medium. People have been using it in fresh water aquariums for years now for these very reasons.

[gordyjamz]

Ok here's my opinion so far reguarding sand. If you don't minda slight haze to your water, I suppose its ok. I'm looking to buy a cartridge. Why you ask, I'll tell ya. We bought our house last year with this pool already here. after two weeks the filter was leaking from the backwash pipe. Needed a new spider gasket. Only 12 bucks at the pool store. OK So I put a new one in, worked fine for the rest of the season. This year it was fine till a few days ago. Guess what its leaking again. It's a hayward swimpro. The guy who sold me the house said he just replaced the sand the year prior(2004). Everyone says the sand should be good for up to 6 years? Well I don't know what to believe. water's hazy. I must say I think i fell for something, because common sense told me " how can water be filtered from sand?" I am still a rather new pool owner who is getting well experienced with addressing problems with algae, filters. etc. And my experience so far is telling me to get rid of the sand filter. Sounds like cartridge is a WHOLE lot easier to maintain. Who can argue with hosing off a filter once a month(10 minutes?), buying a new filter cart. every, what 2 years? versus backwashing, leaking, repairs and such. I may stay away from Hayward too considering the problems with their product. One question I do have for cartridge owners is what size do I get? I have an AG pool 4 1/2 ft, 27 ft diameter round. Hayward 1 1/2 hp pump, 70GPM. Do you also recommend a certain brand other than hayward?

[gordyjamz]

One more thing too, doesn't all that stuff CarlD wrote (6 steps) for cleaner water with sand filter seem like a lot of money and time spent on a device that's supposed to work properly?

[gordyjamz]

Ok here's my opinion so far reguarding sand. If you don't minda slight haze to your water, I suppose its ok. I'm looking to buy a cartridge. Why you ask, I'll tell ya. We bought our house last year with this pool already here. after two weeks the filter was leaking from the backwash pipe. Needed a new spider gasket. Only 12 bucks at the pool store. OK So I put a new one in, worked fine for the rest of the season. This year it was fine till a few days ago. Guess what its leaking again. It's a hayward swimpro. The guy who sold me the house said he just replaced the sand the year prior(2004). Everyone says the sand should be good for up to 6 years? Well I don't know what to believe. water's hazy. I must say I think i fell for something, because common sense told me " how can water be filtered from sand?" I am still a rather new pool owner who is getting well experienced with addressing problems with algae, filters. etc. And my experience so far is telling me to get rid of the sand filter. Sounds like cartridge is a WHOLE lot easier to maintain. Who can argue with hosing off a filter once a month(10 minutes?), buying a new filter cart. every, what 2 years? versus backwashing, leaking, repairs and such. I may stay away from Hayward too considering the problems with their product. One question I do have for cartridge owners is what size do I get? I have an AG pool 4 1/2 ft, 27 ft diameter round. Hayward 1 1/2 hp pump, 70GPM. Do you also recommend a certain brand other than hayward?

[roddiaz1]

I'm thinking of going to cartidge from D.E.. This is my experience: I purchased this house 3 years ago that came with 20' x40' vinyl lined in-ground pool. The pump is a golden hayward (not sure of the specs) and the D.E. filter is a Hayward EC75.

I find that the "life" of my filter is coming to an end. There are a lot of broken plastic parts, non too critical, the pressure gauge sticks, but the filtering ability is no longer any good. Last year I noticed that after regenerating the filter (especially after vacuuming) some D.E. would escape into the pool. Anoying but nothing too terrible. I went through approx. 50lbs of D.E. last year.

This year (after tearing apart the filter and cleaning it thoroughly) upon opening the pool I noticed that my cycles-time between regeneration-were ridiculously short. About 15 minutes! I noticed that my pressure climbs from 5lbs to 25 lbs, before I even put the D.E. in. when I put the D.E. in it remians at 25 lbs and the only further indication I have a clog is that the water flow back to the pool is but a trickle. I can run the filter with the air-bleed open and no spaying...

I called the pool place and they said: Bump and regenerate. I've only done that a dozen times now. I guess I could tear it apart (again) and re-clean it and try agian. I don't know if anybody noticed this yet ,but the EC75 doesn't look like it was designed to be torn apart often...what is it 32 screws???

It is true that my water is particularly swamp and gooey this year upon opening, but the filter is on it's last legs I beleive.

Here is what I beleibe about the cartidge filters. Even if I buy new cartidges every year, it about equal to my D.E. cost (I went through 25 lbs on openning day). And, everytime I replace the cartidges I'll have a virtually new filter. Also, I have several sets of cartidges, so that I can rotate them and while I'm soaking/cleaning one set the other set is working away. I don't think it would be practicle to have several filter nest for the D.E. filter.

Most of the comparisons I have seen are "ideal condition" operating parameters. We know D.E. cleans best, so let's be more praticle, which system is better when the you've got problems (Algae, tubidity, etc.). Which system is more robust (possibly sand)?

Rod

[drumr]

I started with a 150 sq ft hayward missle pro cartridge filter when I bought my 24' AG pool and 1 1/2 hp pump. I stuck with it for 3 seasons before changing to a 200 lb poolco sand filter and very recently a 3/4 hp pump that I have been much happier with. I took the advice of some of the other members here and add a cup of DE everytime I backwash and have a crystal clear pool.

The main reason I switched is because I would spend 45 minutes every other week cleaning the filter with a pressure washer (on its lowest setting). I wasn't saving any water by not backwashing because It would take so long to clean even with the pressure washer.

Now I have about the same filtration (with adding a cup of DE) with just a few minutes of backwashing and no bugs, dirt, and other goop that always would end up all over me before I was finished cleaning cartridge.

[huskerfan]

I love my DE filter! Ya it takes an extra 5 minutes to mix the DE powder with the water... but you'll save much more time by not having to backwash as often. I don't believe in "bumping" it either, it's doing it's job, if the guage reads it needs cleaned, clean it.

I'm a little confused - everyone's trying to get DE filtering quality out of your sand and cartrige filters, why not just use a DE filter?? Our local pool stores totally hate and advised against using a DE filter in our state as we have a high iron issue in our water. I can honestly say that that is even more reason to use a DE filter too! There are a few local people struggling to get the iron filtered out of their pools with their sand filters that the local pool store advised them to get, and have rustish brown water while mine is crystal clear. Take care to not inhale DE by all means, but I'd much rather add my DE powder than my muratic acid!

All boils down to personal preference- a crystal clear pool is a crystal clear pool no matter which way it's achieved!