Filter Replacement - Sand vs. Cartridge ?

[Utlmnop]

We have a sand filter (deets in signature). It's original to the pool (2002-ish). We fought with it the entire season last year (returns sending back the exact junk I was vacuuming up. All recommended solutions for fixing issue failed). I'm fairly certain we have a bad lateral or two. The tank itself has seen better days - with several drain modifications made due to damage during the off/closed season.

I do the bulk of the pool maintenance (hubby does the yard work..) and I work full time and we have two young kids. All that to say - I'm literally the laziest pool owner in history. I want to do the bare minimal work to keep the pool clean. (don't judge. I do what has to be done to make sure the pool is clean and safe - but if there's a way to make that LESS work - I'm all about it)

My husband wants to just replace it with what we have. I firmly believe what we have is a size too small, so at the very least I would replace it with the next size up. But in research - I like the concept of a cartridge filter. Filters smaller particles out of the pool, in theory - requires less maintenance ( I would keep a second set of filters handy for swapping out and cleaning) and it supposedly eliminates the need to backwash and thus refill (we live in an area of Knoxville that has outrageous water costs).

And now I have caused paralysis by analysis.

Go with what I've known for the last 7 seasons? I mean.. I know a fully functioning sand filter will already work 100x better than our broken one, and we hobble by last season with minimal cursing. Or do I go with something that could potentially save me some time and money (In full disclosure - we got so much rain last year that we never had to fill the pool from the hose. So... money savings here might be fictional).

Help?

 

[mknauss]

I am not sure I would say cartridge filters are less work than a sand filter. Backwashing takes just a few minutes compared to nearly an hour to completely break down and clean the cartridge filters. You do not want to let the cartridges dry out dirty so I am not sure I would swap out the cartridges, you would still need to clean the dirty ones right then.

Now, one thing about the cartridge, if you get the largest one available, you may only have to clean them once or at most twice per year. You could even cut that down by getting a robot pool cleaner and discontinue the Polaris. The Robot has its own filter and pump.

You will lose the ability to drain water via waste with a cartridge filter, so look into that. You could plumb in a waste line with some thought, however.

 

[Utlmnop]

You could even cut that down by getting a robot pool cleaner and discontinue the Polaris. The Robot has its own filter and pump.

This is the end goal. I haven't managed to sell the husband on a robot cleaner yet - as "the polaris works just fine" (his words... NOT mine). <sigh> I've half thought of just going out and buying a new one and asking forgiveness later.

 

[mknauss]

I've half thought of just going out and buying a new one and asking forgiveness later.

That is normally the 'male' process!!!!

I say go for it. Call Marina Pool in Denver!

 

[duraleigh]

Take the path you like best but your issue is most probably with your chemistry......not your filter. Most all filters are capable of keepiong a pool very clean as long as the chemistry is maintained. How often do you test? What with? Can you post current test results?

 

[Utlmnop]

Take the path you like best but your issue is most probably with your chemistry......not your filter. Most all filters are capable of keepiong a pool very clean as long as the chemistry is maintained. How often do you test? What with? Can you post current test results?

Appreciated the feedback but I don't have a chemistry issue. When the pool is open (it's currently closed right now - which is why there are no current test results in my post) - I test pH and chlorine daily with a full panel test weekly using a Taylor K2006C test kit. We've had the pool for 7 seasons and I haven't had a CYA, CC, or algae issue in the past 6 season.

The issue with the filter is large particle based - seeing sand, dirt, mulch, etc. being returned into the pool thru the returns- especially while vacuuming. Large - VISIBLE - particulate getting thru the filter -- is a filter issue.

 

[Arizonarob]

I’ll toss my 2 cents into the ring. I have a cartridge filter (oversized) for my pool, and I’ll be cleaning it for the first time since last May. (I don’t really need to, but going to do it anyway) It takes me about 45min to open it up, pull out the cartridges, clean them off, and reassemble.

The trick here (as mentioned) is to have one that is oversized for your pool. With you having a 21k gallon pool, (which is twice the size as mine) even if you went with the same one I have, (4 cartridge) you would be looking at 2 times a year to clean.
For full disclosure, I run hairnets on my skimmer basket, and that cuts way down on smaller stuff making it to the filter.

 

[duraleigh]

I test pH and chlorine daily with a full panel test weekly using a Taylor K2006C test kit. We've had the pool for 7 seasons and I haven't had a CYA, CC, or algae issue in the past 6 season.

So that doesn't sound much like the lazy person you described. Have you opened the filter, and inspected the laterals?

 

[Utlmnop]

So that doesn't sound much like the lazy person you described. Have you opened the filter, and inspected the laterals?

The chemistry stuff isn't hard or time consuming. It's the cleaning part that I try to avoid - top skimming, brushing and vacuuming, etc. IMO - If there was a filter that could work harder so I didn't have to - it would be worth a moderate amount of extra hassle.

I have opened the filter to resettle the sand in attempt to get rid of channeling (I didn't SEE channeling, but it was one of the recommendations on things to do when your filter doesn't appear to be filtering very well), and we acid washed the sand mid-way thru last season. It would still blow larger chunk debris back into the pool. I haven't physically pulled the sand and looked at the laterals. Since the tank itself has some damage - and with the assumption that the laterals were bad - it just made more sense to replace the filter than to try to repair.

 

[duraleigh]

I assume you backwash the filter on schedule. (20-25% increase in psi) Do you notice a significant drop in your psi when you backwash?

 

[borjis]

I have the same sand filter and it works very well.
What you're describing would be very frustrating if mine did that...returning dirt instead of doing it's job filtering.

Me personally....the only thing I have to do is back wash it, once, sometimes twice a year. That's it.
A lot more simple than breaking down a cartridge filter, cleaning them and re-assembly.

If it were me I would fix the one you have or as you suggested, size it up with a new one but bigger.
My pool is only 13,000 gallons so it works well, but for your larger pool a bigger would be better.

And if it helps, if you do get a new robot cleaner, the ones that offer a fine filter (cartridge) basket do
make a difference in clarity when used often. (viewing it under water with a mask or goggles on).

my 002 cents.

 

[Brad_C]

I'm all for oversizing a sand filter. Just make sure you have enough water flow to get it into the proper backwash range, or you'll be forever trying to get it clean.

 

[splashpad]

The chemistry stuff isn't hard or time consuming. It's the cleaning part that I try to avoid - top skimming, brushing and vacuuming, etc. IMO - If there was a filter that could work harder so I didn't have to - it would be worth a moderate amount of extra hassle.

I don't see what size your pump (HP) is and what size your filter is. There is a chance the pump is stronger than your filter size

I have opened the filter to resettle the sand in attempt to get rid of channeling (I didn't SEE channeling, but it was one of the recommendations on things to do when your filter doesn't appear to be filtering very well), and we acid washed the sand mid-way thru last season. It would still blow larger chunk debris back into the pool. I haven't physically pulled the sand and looked at the laterals. Since the tank itself has some damage - and with the assumption that the laterals were bad - it just made more sense to replace the filter than to try to repair.

Did the sand filter ever get run with TFP non-recommended products (esp flocculent)? If the sand has never been deep cleaned, that could be part of the issue.
The laterals are much less expensive to replace (and not overly difficult), vs an entirely new system... but you do note there is existing damage, can you share a picture?

 

[Utlmnop]

As some of you have asked - we did backwash maybe 1x a month - when we saw increased pressures of about 15% or so. It would settle back down to a normal range but would still blow larger items back thru the returns. I swear I vacuumed up the same small - oddly shapped - piece of mulch 20 times before I just got in the pool and hand picked it out!!!!

I'm not privy to what the previous owners used for chemicals, but based on the condition of the liner when we got the house - it was Crud. We did have the sand replaced in the filter back in 2016 (or 2017) when we had our pump replaced. The rodents had eaten even more of the drain plug this winter - which was - overall - the deciding factor in this whole mess. Well... that and my husband not wanting to hear me swear all summer about pool particulate.

So we ended up replacing the filter with a new unit. Settled on a Pentair Sand Dollar SD80 filter. It was installed yesterday! I need to spend some time figuring out how long we need to run the pump/filter now - and at what optimal time of day - and at what speeds. Like Barbie says -- Math is Hard.

But I'm looking forward to a clean pool this season!

 

[splashpad]

I'm not privy to what the previous owners used for chemicals, but based on the condition of the liner when we got the house - it was Crud. We did have the sand replaced in the filter back in 2016 (or 2017) when we had our pump replaced. The rodents had eaten even more of the drain plug this winter - which was - overall - the deciding factor in this whole mess. Well... that and my husband not wanting to hear me swear all summer about pool particulate.

Having a working sand filter will be night & day for your experience! Hoping you stay particulate free!