Sand Filter or Cartridge?? Which is better?

[Aranon]

I understand a cartridge is suppose to be easier maintain and filters better than sand. But now I hear people saying, yes thats true but only when they are barand new. I'm finding out people are spending hours cleaning their cartridges. And I also am hearing they some are having to clean them every two weeks or more. Not the once a season like they advertise. Some say they can never get their filters clean after awhile and have to buy new ones to get that really clean look like they did when they were new. Washing my filters once a month for at least an hour or soaking them overnight in acid seems like a lot of work. Surely a sand filter is not that much work.

I have even got a reply that after two years, one guy was going to get rid of his cartridge filter and buy a sand syste.

So whats the deal. Am I only hearing the horror stories and not hearing from the majority, or are the horror stories the majority?? Someone please advise me. I am torn between a Cartridge filter system 150 Sq ft. Pentair and maybe now a sand filter. Which should I get for a 18' x 40' Oval 54" Thahitian above ground pools. Please advise me. Thank you.
Aranon

[Poconos]

On the old forum the pros and cons of all filters were discussed many times. So, let's start the discussion again. I have sand so I'm biased. Never had anything else. In my opinion, sand is the easiest and cheapest to maintain. However it will miss catching particles that the others will catch. Unless you're a total clean freak sand should be adequate. My water has been totally clear however I do get some fine dust or silt in it once in a while and the solution I've been using for over a year now, add some DE. Silt typically comes from my stream fill water. 9th season now and only thing I replaced was the spider gasket in the multiport valve...once. Sand should last forever. When the pressure goes up some, backwash and you're good as new. Again, my biased opinion.
Al

[duraleigh]

Aranon,

That debate has been endless on this forum and will continue to be so. The sand owners like sand and the cartridge owners like cartridge. Even the ones who have owned both don't seem to have a definitive opinion.

It's not quite Ford vs. Chevy, but it's close.

Okay, Okay, I own sand and I like it best....a cartridge owner will be along soon to sing the praises of cartridges, then a DE guy will chime in on why his is best.

Here is some good advice....whichever one you buy, get it bigger than you think you'll need......everything in your system will function better.

[Aranon]

Ok, hears a thought. What if I used Both. What if I bought a Sand system and hooked up a cartridge sytem to it. The sand filter and pump system would be hooked up like normal but instead of going right back into the the pool have it run into a cartridge filter to filter out the fine particles and then back into the pool.

This would be like drinking water filtration with a coarse prefilter and a fine (polishing) filter.

The Sand Filter would take out all the big stuff (prefilter) and the Cartridge filter would remove all the fine stuff. This way the Sand Filter acts a a pre-filter protecting the Cartridge filter from stopping up. At least in theory.

Any thoughts on this set up. Seems like it would work. Any one tried this yet.

Aranon

[b2001]

What if I bought a Sand system and hooked up a cartridge sytem to it.

I'm pretty sure I've seen a post on this forum in the past advising against that.

But here's an idea. I told you I was going to replace my cartridge filter with a sand filter. What I believe that I am really going to do is get a sand filter and hook it up in parallel with the cartridge filter. I would use parallel piping and cutoff valves so that only one filter at a time is on. I would run the sand filter most of the time because of ease of maintenance poconos refers to and occasionally run the cartridge filter for the "polishing".

I'm not sure I would recommend someone buying two filters as a starter because of the costs vrs. the benefits, but I already have a cartridge filter and I'm planning on buying a sand filter. so I thought I would try to take advantage of the perceived advantages of each. Based on my troubles, I'm still thinking that I will be better off with a sand filter, but I know a cartridge would filter out those very fine particles, after the sand has done most of the work - and I already have one.

[Poconos]

Check this thread. I made comments about adding DE to a sand filter.

http://www.poolforum.com/pf2/showthr...ht=%28ajs-1%29

Al

[waterbear]

I guess I will get into the mix. (these are just my thoughts on the matter, folks! Don't get too bent out of shape if you disagree with me! As Al and Dave indicated this is and probably always will be an endless debate!
I like cartridges because, IMHO, the are easier than DE to maintain and give almost as polished a water quality (DE filters to about 5 microns and cartride to about 20). Sand will filter to about 60 microns so it will never get the water as polished as the previous two but it is probably the easiest to care fore. I have had cartridge filters on a portable hot tub, my current pool/spa combo, and on numerous aquariums (talk about a gunked up cartridge...probably worse than Biguinide "goo"!)
I have found that a quick hosing BEFORE the pressure climbs up 10 psi as recommended greatly extends the life of the cartridge, I hose mine off about once a month and the whole process takes about 10 minues including cleaning the skimmer basket in the pump!
The cartridge does need cleaning (soaking) when a lot of organics build up on it. I have been doing a bit of reseach on it and have found that many OEM replacement manufacturerer's recommend soaking in TSP and water and one Austrailian spa equipment company recommomds soaking in a bleach solution (which is also what the aquarium filter manufacterers recommend...btw one of the largest manufactuers of aquarium cartrdige filters is Pentair! The frequency of soaking depends on the bioload (scum, oil, etc.)the filter is filtering My spa used to need it about once a year and my aquariums maybe every 4 months,
If there are any scale deposits then you need to soak in an acid bath to fizz them away.
Now if this sounds like a lot of work then just break down, clean, and reassemble a DE filter!. Yes, it is easy to 'bump' them but all you have done is mixed the dirt and the DE and the filter medium is still dirty and likely to restrict water flow. You can backwash them, but IMHO, not a good idea since you have no idea how much DE you flushed out so you really don't know how much to put back in. You run the risk of either not having enough DE in the filter and plugging the laterals with dirt or having too much DE which, in a worse case,can mean having to take the filter apart and literally chop out the hardened DE inside the filter! I admit that is a relatively rare occurance but it does happen!. IMHO, if a DE filter is dirty (and they get dirty enough to restrict the flow through them pretty fast!) it should be broken down and cleaned.
If you don't care about the work involve then DE WILL give you the cleanest water you can get! I am personally a bit too lazy for that and my brother has a DE filter so I have some first hand experience with them too.
(have used them in aquariums also. basically the same on a smaller scale)
Sand is easiest to maintain, Backwashing is very effective, but they are the least effecient of the 3 types of filters at polishing the water. To me a big drawback!
I guess what it all boils down to is to weigh the pros and cons of each type and see what you are willing to put up with!
I opted for almost DE water quality and more work than sand but less than DE and don't mind the expense of replacing the cartridge about every 5 years. I also have the most experience with cartridge filters so I am comfortable with them. I know how they will perform and I know what I need to do to keep them happy!

[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.)