Change from Sand Filter to Cartridge Filter ?

richmgreen

LifeTime Supporter
May 26, 2010
305
Central Connecticut
Pool Size
26700
Surface
Vinyl
Chlorine
Salt Water Generator
SWG Type
CircuPool RJ-45
I've read many of the posts about sizing of the filter and remain confused. Given I have and 18x36 pool with a deep end of 8', I estimate 27,000 gallons. I have a 1 1/2 HP pump. I realize bigger is better, but I do want to be reasonable on cost as well. Will a 325 sqft work? Do I need over 400 sqft? I assume I can not go less than 325sqft.

Please help!

Thanks
Rich
 
A Pentair Clean & Clear 420 or 520 should work fine. The larger the cartridge surface area, the longer you can go between cleanings.
 
Curious why you are ditching your sand filter?
A couple of reasons. Tired of backwashing and losing water/chemicals, but mostly I am draining to a neighbors property ... which has been an issue for years. The people that had the house before us put the pool in the back corner of property. Nowhere to drain other than on neighbors land.
 
Hey Rich !! What’s your yard and neighbors yard look like ? I ask because a 300 range filter would do fine with filtering just your water, but if you have trees/pollen or other various crud it would struggle when everything was dropping. Scratch that, it never struggles, it does it’s job and filters, but you’d be dirty 40% quicker than a 500 sq ft.

Think of it as how many 5 gallon buckets of crud blows through you yard. It all stops at the pool like a snow fence. So you get whatever actually falls in, *plus* whatever blows in and sinks immediately. If you never get enough stuffs to fill a 5 gallon bucket, the smaller filter only needs to to regular water filtering. If you get multiple buckets you’ll need the bigger filter.

If you were to go with a 300 range, The worst that can happen is you need to break apart the filter and clean it once or twice during pollen / farm dust season. But it gets old on year 7... or 2. Lol.

Kinda like SWGs, The original buy in costs the bulk of the money. It’s only a couple hundred dollars to go bigger and you’ll thank yourself many times down the road when you don’t even remember spending that $250.
 
Hi. I currently have Hayward 24” Sand Filter with 1.5 HP pump. Pool approx 26,700 gal. 18x36 with 8’ deep end. Looking to switch to Cartridge filter for
1) Better filtration
2) Stop backflushing into my neighbors yard 😀

Any recommendation ? 325sgft or more? Hayward vs Pentair vs Doheny’s own brand ?

Thanks
Rich
 
Rich,

I have a Pentair CCP-520 and love it.. I like the dirt simple plumbing, no backwash or MPV to fool with..

That said, I don't get algae and I don't close my pool. If I did, I doubt I'd get a cartridge filter..

I clean my filter twice a year which is not a big deal at all.. If was trying to SLAM my pool, I'd have to clean it once a week or more and that would be a pain.

Thanks,

Jim R.
 
Directly behind my pool fence is my neighbors farm land. He does hay bailing and fertilizing. Also, we do get a lot of pollen early in season. Should I abandon the cartridge filter idea ? 😀
 
Some more info:

Directly behind my pool fence is my neighbors farm land. He does hay bailing and fertilizing. Also, we do get a lot of pollen early in season. Should I abandon the cartridge filter idea ? 😀

But the back flush water runs down toward his yard/garden.
 

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Not often at all during the season. More often when first opening. I was thinking that I could turn the water over faster with the cartridge filter and run the pump less hours ?
 
I believe all my piping is 1 1/2". So, doesn't that mean a max of 60 GPM for my system. Was hoping a sand filter would give me higher GPM and thus turn the water over in less time. But, that might not be the case since my plumbing is not 2" ?????
 
Turnover is meaningless. You run your pump to distribute chemicals and/or create chlorine and skim the surface.

Like Jim asked, how often do you have to backwash? If few times each year, then a cartridge filter would be fine. If many times each year, then you might stick with the sand filter.
 
*if you need to backwash many times a season, a bigger *any* filter will help greatly. Might as well swap to honking cartridges at that point.

I had 500 sq ft on 35k gallons. Even with insane pollen they did great. So much so I’m sticking with them on my upcoming build instead of switching to the larger 500s in a different unit.
 
You might also consider a long backwash hose to get the backwash water away from the neighbors property. They sell 50ft or even 100ft sump pump hoses that work well, I use a 25ft hose.

Just an option I’d through out there.
 
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I'm having no cleaning issues. Water is sparkling clean in summer. I don't backflush often either. But again, I wanted to stop draining onto my neighbors property and turn over the water in a shorter amount of time by increasing the flow rate above 60gpm. Sand filters, because of the MPV are restricted in flow rate. (Less then 60gpm). If I can turn my water over in 5 hours vs 10, then I could potentially run the pump less. However, I think I have all 1-1/2" piping .... so my flow rate is probably restricted to 60gpm anyway. Whole point of turnover rate is to filter every gallon of your pool water at least 1-2 times/day.
 
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Whole point of turnover rate is to filter every gallon of your pool water at least 1-2 times/day.

Rich,

It is your pool, and you can do anything you want, but please understand that the idea that you must "turnover" X amount of water per day, or times per day, is just a myth. It is just not true.

If you only what to run your pump for 5 hours you can do it with the filter you have.

Thanks,

Jim R.
 
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It is your pool, and you can do anything you want, but please understand that the idea that you must "turnover" X amount of water per day, or times per day, is just a myth. It is just not true.
Sorry, don't mean to hijack this thread....
Could you please elaborate more on why it's just a myth.
As a noob, I keep hearing from multiple sources (and I mean just about everywhere) about the importance of water turnover.
 
For it to not be a myth, you would need a separate holding tank the same size as your pool as when you are 'turning over', you are also mixing. The first pass nets about 65% of the water through the filter in perfect conditions and the second pass nets about 85%. Each subsequent turnover nets a smaller percentage and you never get it all.

In reality, the filtering demand changes through the season and you need more filtering in the spring/fall and less in the mid season with less crud falling. Even two neighbors will need completely different amounts of filtering so the idea that every pool in the world need the same amount of filtering is hogwash.

Just like chemicals, your pool needs the what *it* needs, not a one size fits all approach. If it's nice and clear, you can lower filter time if you wish. If it isn't properly skimmed/filtered, you need more. It will tell you everything you need to know if you listen to it. (y)
 

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