Pros and Cons of Sand vs Cartridge Filters???

[cubbybeave08]

I currently have a cartridge filter...After 8 years maybe 9...I'm not a fan. I am thinking about switching out to a sand filter. Why do those of you who have sand filters choose sand over cartridge filters? What if any drawbacks are there. The biggest draw back I see is that my cartridge filter doesn't filter out all of the little specks of pollen that seem to either not get trapped in the filter, and blow right back in...or it just swirls around the cartridge and blows back in. I have grown tired of vacuuming and two hours later all the pollen is back on the bottom of the pool. It's been that way for years.

My personal feeling with all the trees around my back yard, the cart just isn't filtering out the fine pollen which then just settles back down. Any thoughts and suggestions. I'm really tired of buying new cartridges every three or four years.

What are the drawbacks of having sand vs cartridge? Any?

Cubbybeave wants to know!

 

[Philo]

My next filter will a DE.

The water looks "polished".

 

[richierich]

I can't speak to a sand filter since I never had one. What size is your cartridge? Perhaps its undersized? Are you using hairnets in your skimmer basket to cut down on cleaning your cartridge?

I clean my cartridge about 3 times a year. I love it. I would never use a sand filter. I see so many posts about people having problems with them. Like I see people say sand is getting in the pool because of a broken lateral, or problems backwashing.... You rarely see anyone post about a cartridge filter problem.

 

[Donldson]

I switched from a cartridge filter to sand this past year and am happy with the decision thus far. Most importantly is remembering that clear water starts with chemistry, a sand filter may have trouble keeping up if there is always a nascent algae problem, but if the chlorine level is correct then it will have no problems at all. My water was actually a bit clearer because I would push the cartridge cleaning off as long as I could because of the hassle of it, while I will backwash as soon as is required since it is virtually no work at all. On top of that, a little DE in a sand filter will "polish" the water just fine.

That's not to say I wouldn't use a cartridge system in the future if it were properly oversized, but if a sand filter will do the job at a fraction of the maintenance then I'm in. As far as problems, yep, sometimes parts break. They do on cartridge filters too but most often it is the cartridge itself that is what needs replaced and since that is just assumed to be a normal thing people don't post about that. You can also find plenty of posts about filter housings that have cracked, a situation that requires complete replacement. But IMO the bottom line is if you keep your chemistry in line then your pool will be clear no matter what filter type you use.

 

[wjr75]

Sounds like you may have a tear in your filters cleats or it's not seated properly. Cartridge filters I believe should filter finer particles than a sand filter. Of course it needs to be sized properly. My parents have a sand filter in the pool that I installed 30 years ago and still seems to do a decent job. You just need to backwash every few weeks or so. Cleaning the cartridges are pain but I only need to do mine once a year in the beginning of the season.

 

[richierich]

Sounds like you may have a tear in your filters cleats or it's not seated properly. Cartridge filters I believe should filter finer particles than a sand filter. Of course it needs to be sized properly. My parents have a sand filter in the pool that I installed 30 years ago and still seems to do a decent job. You just need to backwash every few weeks or so. Cleaning the cartridges are pain but I only need to do mine once a year in the beginning of the season.

haha I actually find the cleaning of cartridges oddly calming. Plus my kids LOVE using the hose to clean it.....

 

[Dodger]

Sorry, I can't comment on the difference between filter types, but I can share our pollen + cartridge filter situation.

We have a fair amount of yellow pollen trees around our house. For many months during the year, you can see it on the cars, the driveway, the brick, and of course, the pool. In the worst months, it collects on the tile around the water line, which is one of my triggers to run the Sheer Descents to stir things up and move more surface water to the skimmers.

I clean my filter cartridges regularly (in fact, just did it this morning) and the yellow pollen is one of the main items that washes out every time. Based on that observation, I'm pretty comfortable that the 30-month old cartridges are catching a good portion of the pollen. Also, I do not have any visible pollen coming back through my returns and the floor stays clean for days after I vacuum.

I am curious about the way you described stuff blowing back in or swirling around the cartridge. Can you see it coming back in through the returns? Is the accumulation below the return area?

 

[needsajet]

I like sand filters because they're little fuss, no-mess, easy to use, and low ongoing cost, but as Donldsn says, water chemistry is first and foremost. Sometimes if you have nascent algae (free-floating, not visible), the dead algae "carcasses" will fall to the bottom and look like brown, grey or yellowish dust. You can rule out algae with the Overnight Chlorine Loss Test.

If it's just dust and pollen, your cartridges should be catching it, so if they're not damaged and seated correctly, I'd think about what's needed to get the pollen off the bottom and into the filter. A cleaner would do that job for you. More skimming might also be helpful, as will finding a dirtiness level that gives you the best filtering.

You will see more threads here at TFP with questions and trouble-shooting of sand filters, but I believe that's because they're the dominant filter type, and perhaps because they usually have multiport valves. An advantage of cartridge is no multiport valve, which eventually require a new spider gasket.

 

[crabboy]

Iv'e got a cart and love it. Clean it once a year, have had the same four carts in there since we built the pool, over 10 years ago. We have horrific pollen in North GA in the spring, everything turns green from the pine pollen and the cartridge filters keep the pool super clean.

No backwashing wasting my treated (and possibly heated) pool water, no messy sand replacement, no channeling.

About 2 hours once a year is all the maintenance my cartridge filter requires.

 

[Catanzaro]

Use of skimmer socks is highly recommended. Maintenance on a sand filter is a breeze. Backwash before closing the pool and about one day after opening the pool and nothing in between. The socks really do help a lot. I keep 2 extra sets with socks ready to be swapped out during the pollen season and then clean all 3 sets at once.

It appears that you have issues with your cartridges as mentioned in the previous posts, as the filtering is just a notch above DE filters.

 

[YippeeSkippy]

The way I see it is sand filters are cheap and easy to work with especially for new pool owners... yet *if* you have algae, they are the slowest to clear it.

Cartridge filters are good for areas with very costly water. They only require an occasional cleaning. The bigger the cartridge, the less often the cleaning.

DE is the like the finest filtering out there, but it can be a bit of nuisance to deal with at times and it WILL catch EVERYTHING you got in that water...which in the case of algae will require the most attention.

BOTTOM LINE: Keep your water clean and tested and any filter will work for you.

My two cents :blah: lol

Maddie

 

[cubbybeave08]

Guys...I am a pool chemistry enthusiast. I have been using BBB since 2008. I know how to keep my water clean. That isn't the issue. This is pollen on the bottom of my pool and it drives me crazy. It is because I am so on top of my chemistry that I have issues with this stuff floating on the bottom settling into the divots and crevices in the bottom of my pool. We have a huge pollen problem where I live. yellow pollen to be exact. Lots of pine trees and other trees. We see it on our glass patio table it has to be washed every couple of years. I only had a problem with algae this year because I got lazy toward the end of the season and did not take care of it like I should have. Otherwise, I never have algae. My problem is that I want to be able to vac this stuff up and not have it come back through...It is the only thing I can think of...I vacuum it up and in two hours I have it all on the bottom of the pool again.

I have a two horse power pump, and I think the Hayward cartridge is a 125 to 175. It is about 3 feet tall and kind of skinny. I just think that a sand filter will do a better job of filtering out this fine pollen so I don't have to vacuum each time I want to just get in and enjoy my pool. I shouldn't have to vacuum each time I get in...just so I don't have to look at this garbage. And just so you all know it is not Algae...I have overnight FC tested my pool to death over the past 8 years...it is not pollen. MY FC holds...and the water is always crystal clear. ALWAYS. I use skimmer socks usually doubled so much so that they usually get so clogged it actually restricts the water flow. Nothing seems to help. Just want some advice on what to use...I am at a loss.

 

[cubbybeave08]

Sorry, I can't comment on the difference between filter types, but I can share our pollen + cartridge filter situation.

We have a fair amount of yellow pollen trees around our house. For many months during the year, you can see it on the cars, the driveway, the brick, and of course, the pool. In the worst months, it collects on the tile around the water line, which is one of my triggers to run the Sheer Descents to stir things up and move more surface water to the skimmers.

I clean my filter cartridges regularly (in fact, just did it this morning) and the yellow pollen is one of the main items that washes out every time. Based on that observation, I'm pretty comfortable that the 30-month old cartridges are catching a good portion of the pollen. Also, I do not have any visible pollen coming back through my returns and the floor stays clean for days after I vacuum.

I am curious about the way you described stuff blowing back in or swirling around the cartridge. Can you see it coming back in through the returns? Is the accumulation below the return area?

Sometimes I can see it blowing back through the return...as I vacuum. especially when I have large amounts of it after a cold snap and no one has vacuumed or swam. Also a question, I have a two hp pump...is that too much pump for a cartridge filter...does it pull too much water through too fast. It is what came with the pool. Does that have any bearing on the effectiveness of filtration? Also...because you live in a heavy pollen area, how do you clean your cartridge to keep it filtering? Just rinsing with hose, or do you do deeper cleaning?

- - - Updated - - -

I switched from a cartridge filter to sand this past year and am happy with the decision thus far. Most importantly is remembering that clear water starts with chemistry, a sand filter may have trouble keeping up if there is always a nascent algae problem, but if the chlorine level is correct then it will have no problems at all. My water was actually a bit clearer because I would push the cartridge cleaning off as long as I could because of the hassle of it, while I will backwash as soon as is required since it is virtually no work at all. On top of that, a little DE in a sand filter will "polish" the water just fine.

That's not to say I wouldn't use a cartridge system in the future if it were properly oversized, but if a sand filter will do the job at a fraction of the maintenance then I'm in. As far as problems, yep, sometimes parts break. They do on cartridge filters too but most often it is the cartridge itself that is what needs replaced and since that is just assumed to be a normal thing people don't post about that. You can also find plenty of posts about filter housings that have cracked, a situation that requires complete replacement. But IMO the bottom line is if you keep your chemistry in line then your pool will be clear no matter what filter type you use.

Yeah...please understand...I am a chemistry expert when it comes to sanitizing water...I have cleared all of my neighbors pools at one time or another so they don't get taken to the cleaners at the pool store. I get the chemistry. I test several times a week for FC, CC, PH and monthly for CYA and ALK. I'm on top of it. When you talk about sizing the filter. I have the filter cart in the same size it it came with when I got the pool. Does the 2 HP pump have any bearing on filtration. Is it too big?

 

[Poolzzz]

...Sometimes I can see it blowing back through the return...as I vacuum...

This doesn't seem right to me. My pool lives in a tree lined, pollen invested area and I've vacuumed up all kinds of stuff and never see anything coming back through the return. A good cartridge filter will capture everything that is visible.

With your 150 ft² filter size you shouldn't be having a problem with blow through. I've tested flow rates up to about 3gpm/ft² of filter area without any problems.

Personally I think you have a problem with your filter system if you see stuff blowing out of the return. Something isn't sealing or the media has been damaged.

Regardless, if your reason for switching to sand is for better filtration I think you'll be disappointed. Sand doesn't filter as well as a good cartridge filter.

 

[cubbybeave08]

This doesn't seem right to me. My pool lives in a tree lined, pollen invested area and I've vacuumed up all kinds of stuff and never see anything coming back through the return. A good cartridge filter will capture everything that is visible.

With your 150 ft² filter size you shouldn't be having a problem with blow through. I've tested flow rates up to about 3gpm/ft² of filter area without any problems.

Personally I think you have a problem with your filter system if you see stuff blowing out of the return. Something isn't sealing or the media has been damaged.

Regardless, if your reason for switching to sand is for better filtration I think you'll be disappointed. Sand doesn't filter as well as a good cartridge filter.

Poolzzz do you think the 2 hp pump is too strong...I don't see anyone using a 2 hp ever on these boards. Should I step down to a two speed. Could the water be damaging the filter pleats because it is coming through too fast...creating too much force. The pump outlet goes right into the filter with just a two way valve in between Could 2 HP pump be damaging the filter at that level. Mind you...I have had this problem for all of the 8 years I have had the pool. And the only thing I can think of is that it is the pump. It creates quite a lot of suction when vacuuming. Could that be the culprit?

 

[Nectarologist]

I don't see any drawbacks to one type vs the other. Just that you need a place to backwash the sand filter water whereas you need a place to rinse off the cartridges off. Sand filters have a larger footprint so make sure it would fit your existing setup before you decide for sure. If you really feel it's a filtering problem go with DE or keep the cart (sand as a last option for filtering capabilities but see below).

Since you can actually see debris coming back into the pool then the filter is not working properly (in this case cart). Once you see debris the cartridge itself is totally full and cannot filter anymore (or as mentioned there is a hole in it). 2 hours to see pollen accumulating on the floor is not something that's going to come from the sky that quickly, it would have to be the existing debris settling again. I change my cartridges every 3-4 seasons so I don't think that's unusual especially if you get a ton of pollen.

As mentioned cartridge filters catch/clean smaller debris than sand does (with DE capturing the smallest sized particles). But we're talking microns so to the human eye we couldn't tell de from cart from sand filtered water (all other things being equal).

The pump is large for the pool but I don't know that it would damage the cartridge pleats. Check with a cartridge manufacturer to see if there is a flow limit to them. Do you remember what the pressure was when they were new? If it was very high when they were new maybe you're on to something.
Good luck

 

[Dodger]

Sometimes I can see it blowing back through the return...as I vacuum. especially when I have large amounts of it after a cold snap and no one has vacuumed or swam. Also a question, I have a two hp pump...is that too much pump for a cartridge filter...does it pull too much water through too fast. It is what came with the pool. Does that have any bearing on the effectiveness of filtration? Also...because you live in a heavy pollen area, how do you clean your cartridge to keep it filtering? Just rinsing with hose, or do you do deeper cleaning?

I clean my cartridges with a hose and jet spray nozzle. I can do all 4 cartridges (Pentair CCP420) in <30 minutes since we got a new higher diameter hose.

As far as your pump size, I run my 1.5HP VS pump at max (3400rpm) when I vacuum. The higher speed is a big help grabbing dust and leaves, and there is no visible dust in the return.

If it was me, I would reinspect the inside of my filter housing. I would look for a crack in that plastic cartridge seat at the bottom. Look at the top side and the underside. If it's cracked, I'm wondering if the weight of the cartridges pressing down on it could create a pathway for unfiltered water back to the return. I would also double and triple check that there are no obstructions (sand, rocks, gunk) between the bottom of the cartridges and that seat.

Edited to add: I'm assuming you've recently cleaned your cartridges and inspected for perforations or broken bands.

 

[needsajet]

Great explanation above about the seats and surfaces and possibilities for poor seating of the cartridges!

For inspecting a cartridge itself, some people will take it into a dark room, close off one end with a piece of cardboard held over it, and shine a flashlight inside. The light you see through the pleats should be fairly even looking, and pinholes or larger will show up quite easily.

As far as pump size, 1.5 HP is probably the most common, but 2 HP is not that unusual. Lots of people here with 3 HP. Pump is not the problem, I'd say.

 

[Teald024]

Poolzzz do you think the 2 hp pump is too strong...I don't see anyone using a 2 hp ever on these boards. Should I step down to a two speed. Could the water be damaging the filter pleats because it is coming through too fast...creating too much force. The pump outlet goes right into the filter with just a two way valve in between Could 2 HP pump be damaging the filter at that level. Mind you...I have had this problem for all of the 8 years I have had the pool. And the only thing I can think of is that it is the pump. It creates quite a lot of suction when vacuuming. Could that be the culprit?

A cartridge filter will filter smaller particles than a sand filter will. So if you truly believe that the pollen is going through your cartridge element, then getting a sand filter won't help. I clean my filter in the spring after running for a couple of days and then again in the fall right after closing and I disconnect the plumbing. It's dirty to the eye, but the filter pressure didn't show much change on the gauge. since the spring.

I have a very similar setup. My pump is a 2-spd however. Your filter probably has a 150 or 175sqft cartridge. Even with 80gpm flows, which is likely much higher than reality, the flow through the filter is relatively low with the large surface area. The large area is to give plenty of surface to catch all the junk in the water. The hose cleaning process is much more harsh than regular use in your system.

If you are seeing visible particles in your return, then there may be holes in your cartridge, a crack in the rubber ends of the cartridge, or it is somehow not seating properly and water is bypassing the cartridge.

As to your specific question about a 2hp single speed pump being too big. I would consider changing it out. Not because your filter can't handle it, but because a 1.5 hp 2 speed pump will give you considerable energy savings. I wouldn't consider this a step down. I believe it is an upgrade. I usually run my pump on LS most of the time and HS only when I want to vacuum or shoot my homemade fountain really high/far. You could likely cut your electricity usage in half without sacrificing any water quality.

 

[cubbybeave08]

A cartridge filter will filter smaller particles than a sand filter will. So if you truly believe that the pollen is going through your cartridge element, then getting a sand filter won't help. I clean my filter in the spring after running for a couple of days and then again in the fall right after closing and I disconnect the plumbing. It's dirty to the eye, but the filter pressure didn't show much change on the gauge. since the spring.

I have a very similar setup. My pump is a 2-spd however. Your filter probably has a 150 or 175sqft cartridge. Even with 80gpm flows, which is likely much higher than reality, the flow through the filter is relatively low with the large surface area. The large area is to give plenty of surface to catch all the junk in the water. The hose cleaning process is much more harsh than regular use in your system.

If you are seeing visible particles in your return, then there may be holes in your cartridge, a crack in the rubber ends of the cartridge, or it is somehow not seating properly and water is bypassing the cartridge.

As to your specific question about a 2hp single speed pump being too big. I would consider changing it out. Not because your filter can't handle it, but because a 1.5 hp 2 speed pump will give you considerable energy savings. I wouldn't consider this a step down. I believe it is an upgrade. I usually run my pump on LS most of the time and HS only when I want to vacuum or shoot my homemade fountain really high/far. You could likely cut your electricity usage in half without sacrificing any water quality.

So why can't I keep the pollen off the bottom of my pool??? I clean the filter when I put it in...I clean it two or three times per summer. I don't know why I can't keep the bottom clean. I vacuum it up...Clogs up a skimmer sock...and then two hours later...all over the bottom of the pool again. And I repeat...you could drink my pool water.

Chlorine is always between 4-7 ppm
CYA is kept at 40 ppm
pH is 7.3-7.6
Alk is 90 to 110 ppm

ALWAYS. I test the crud out of my water.