Which Filter to Get??? DE vs Cartridge???

[jblizzle]

Just a couple corrections/comments:

Cartridge, and DE require them to be opened up and taken apart to be cleaned occasionally (definition of occasionally depends on many factors) especially in the advent of an algae bloom.

True, but we also advocate opening up a sand filter once a year to clean the sand as well.

De filters can't really filter to waste so if you have a particularly bad dirt infusion from a storm you can't just vacuum the pool - you have to charge and clean the filter over and over again.

DE filters can certainly pump to waste just like a sand filter if you have a multi-port valve ... mine all have.

Cartridge filters need to have the cartridge out and soaked in a garbage can full of TSP or some other cleaner at MINIMUM once or twice year which if you have spare isnt a big deal- but you cant get really big cartridge filters and if you have a dust problem or high influx of debris like I do- the dream of once or twice a year cleaning goes down the drain and you are inside the filter over and over.

You can get huge cartridge filters and many members only clean once a year. I also do not think a TSP soak is required as often as you claim.

If you are running a variable speed pump and tuning the RPM down to save money a 1-2 lb rise in backpressure can effectively halt the flow leaving you with 2 choices - bump the RPM spending more money and forcing the flow, or backwashing which is a chore on Cart and DE filter. If you are just running a 1 HP pump it will force system even with 10 pounds of backpressure but you arent saving any money on electricity.

We recommend cleaning any filter when the pressure rises 20-25% over the clean pressure, this should be checked on a higher RPM / high speed. A 2psi rise on low speed could easily be a 100% increase in the filter pressure, so certainly the flow rate will suffer. As mentioned before, cartridge filters had lower head loss as well and thus would allow greater flow rates for a given plumbing setup.

Sand filters are a snap to backwash, can vacuum to waste, offer comparatively large surface areas of filtering and a greater degree of sizes, and when filled with zeo type media offer DE, or near DE filtering.

Sand filters are certainly the least maintenance, but they are not the only filters that can vac to waste. A simple 3-way valve added before a cart filter can allow the same thing. Once you get to very large pools, I also think it is easier to find appropriately large cartridge filters than it is to find sand filters that are large enough.

Been there, done that forever - sticking with a sand filter and zeo style media.

It really is personal preference. They all have pluses and minuses. And we have seen time and again that ANY of the filter types can keep a pool crystal clear.

 

[Davegvg]

TSP or cleaner - I would have to soak mine or they would start to have debris stick to them. I would highly recommend on a twice a year clean that you soak them or if you are doing an algae removal.

Maybe I overdid it.

The older they were the more frequently they would need to be soaked.

What is the TFP verdict on the average cart lifespan?

Filter physical size is one thing - filtration area is something else. Never seen cart on a commercial pool but maybe they do make them that big. The square feet of filter medium between a cartridge and a sand filter with zeo isnt even close. A tablespoon of zeo has bout 100 yards of surface area.
The unequivilant surface area is likely the head pressure diff.

Lots of guys havent open their sand filters for years and there is great debate about this here on TFP.
Even if we say clean it once a year the sand filter wins the ease of use battle hands down.

Has TFP rendered a verdict officially about this?

I looked in our description page and didn't see this recommendation. pool-school/cleaning%20pool%20filters

Like the claim of twice a year cleaning- your mileage may vary.
Some guys need 2 - for others 6 some 10. (look at geekgranny)

Never seen a 3 way on a de filter -thanks for that correction. I dont think it would have been possible on my first de filter with a lever on the bottom, but I should have ordered it for my pentair quad de but never saw the option.


Uncle Dave

 

[duraleigh]

Has TFP rendered a verdict officially about this?

Yes. The official verdict is, "There can be no verdict"

There is probably no discussion beat more to death than one type of filter over another.....there is no winner.

Even the zeo you have had such great success with seems to vary from user to user so that verdict is out too.

What is consistent throughout these 10 years of discussions is that virtually everyone likes the type filter they have. I have sand and I like it Others have carts and they like carts. etc. etc.

As jblizzle said above, what has been proven over and over is you can have a crystal clear pool with all three types if you manage your chemistry and mechanical equipment properly.

 

[jblizzle]

I have no experience with cartridges, but I think many members have them for years with no issues.

I don't think you can really look at the filtration area as you are suggesting. A 12" zeo-sand filter will not work as well as a 20+" regular sand filter just because the zeo has more surface area. I was no considering commercial sized pools as that is not what we are mainly about ... they have the room for gigantic sand filters and like the ease of use. BUT, for homeowners, they may not have room for those huge filters. Here are a few examples of our size recommendations:

For a typical residential 20k pool: 300 sqft cart, 56 sqft DE, 3.7 sqft (26" diameter) sand
Any of these are reasonably sized and easily sourced for a homeowner

For a pretty big 35k pool: 520 sqft cart, 100 sqft DE, 34.5" diameter sand
That is becoming a pretty large footprint for the sand filter and the cartridge is not huge.

Breaking down any filter every year or so is a good idea, so not sure why it would not be a good idea to "clean" the sand also.

And certainly the frequency of filter cleanings if variable based on debris load, chemistry, and filter size. Unfortunately, the last is what is often a driving factor as many pool builders spec a pump that is too big and a filter that is too small.

I said you could put a 3-way valve before a cartridge filter to have a waste option. My DE filters have had the same 5-6 way multi-valves that sand filters often have. Alternatively I think both a sand and DE could have the basic backwash-only plunger valves (which certainly leave you without the waste option).

 

[mas985]

I am going on year 9 with my cartridges and as I mentioned before, once a year cleaning with barely a rise in PSI (< 0.5).

 

[Davegvg]

I am going on year 9 with my cartridges and as I mentioned before, once a year cleaning with barely a rise in PSI (< 0.5).

Thats awesome is that the normal lifespan?

UD

 

[jblizzle]

I am going on year 9 with my cartridges and as I mentioned before, once a year cleaning with barely a rise in PSI (< 0.5).

Thats awesome is that the normal lifespan?

UD

I see you have an engine for your avatar ... let me ask you this ... What is the normal lifespan of a motor / car? ... probably depends on a lot of factors huh?

 

[mas985]

With a large filter, it doesn't need cleaning very often so there is less chance of damage. Also, having a low HP pump helps to keep flow rates down which can also damage the filter.

But then again, I am also still on my first SWG cell going on the same 9 years so maybe it is just luck or maybe good chemistry.

 

[Davegvg]

I am going on year 9 with my cartridges and as I mentioned before, once a year cleaning with barely a rise in PSI (< 0.5).

Thats awesome is that the normal lifespan?

UD

I see you have an engine for your avatar ... let me ask you this ... What is the normal lifespan of a motor / car? ... probably depends on a lot of factors huh?

Its a boat engine...not as long as Mass's filters thats for sure.

I ask because I saw a thread here talking about three years- but yes as usual.... YMMV.

UD