Pool filter sizing - time to upgrade?

[tikoh]

I've been spending my COVID time slowly making small upgrades to the pool. I've straightened out some plumbing headaches and upgraded to a VS pump. The next thing I'm looking at is the sand filter. I have a Sta-rite BP-200-1 sand filter for my ~36,000 gallon pool. It was installed in 2006 sitting in the dirt with no base, so it's kind of sunken down and I've had to dig out a space to get to the drain at the end of every season since we've had the house (this is the 3rd summer). As part of my rearranging of things I'm putting a new equipment pad down so I was planning on changing out the filter sand while I move it. Looking through the manual to see how much sand to order, I realized that I think this filter is very very undersized for my pool. Am I wrong about this?

If you all think I should upgrade, I have a few questions...I really really like the idea of a cartridge filter, but always assumed that because of the size of my pool it would be ridiculous. Looking through the options now, there are many that have better flow/turnover rates than the filter I have now. Is there a good reason not to get something like this? sku-page

8-hour turnover rate is listed at 72,000 gallons as opposed to 21,000 gallons for my current filter (I realize that my pump isn't going to push that much water through either filter, but this is how we compare filter capacities, right?)

The price difference for the cartridge filter isn't that different that an appropriately sized sand filter.

Thanks for any advice or input!

 

[splashpad]

... upgraded to a VS pump ... I have a Sta-rite BP-200-1 sand filter for my ~36,000 gallon pool...
... appropriately sized ... filter

So your filter needs to handle the same or a higher flow rate than that from your pump. Otherwise the pump will force the particles through whichever filter you have, reducing it's effectiveness/life.
Pool Filter Comparison - Trouble Free Pool ~ Pump Basics - Trouble Free Pool

 

[tikoh]

Right, and with the VS pump, 90% of the time I'm going to have pretty low flow, but would definitely overpower the current sand filter at higher pump speeds. Before I had the VS, the pump that the previous owner had would have been constantly exceeding the max gpm of the filter.

 

[sktn77a]

I believe your current filter takes 200lbs of sand. That's good for ~ 10,000-15,000 gal pool.

Do the math!

 

[Newdude]

Hey Tikoh. I have your pool with a 500 sq foot filter compared to that 200. If you have trees/ pollen/ farms / general debris around you the 200 will probably need monthly cleaning.

 

[tikoh]

Would that 500sq ft rating apply to both sand and cartridge filters?

Hey Tikoh. I have your pool with a 500 sq foot filter compared to that 200. If you have trees/ pollen/ farms / general debris around you the 200 will probably need monthly cleaning.

 

[Newdude]

Would that 500sq ft rating apply to both sand and cartridge filters?

They are rated differently in that capacity. The filter you linked to was a 200 sq ft cartridge and among the smaller ones for your pool. If you go the cartridge route get the biggest you can, or close enough like the 500.

 

[tikoh]

Newdude, sorry I wasn’t thinking. Obviously 500 sq ft is ridiculous for a sand filter.

Where does the 500 come from for a cartridge filter? According to Pentair the 200 should be fine for flow. Does it have to do with cleaning frequency?

 

[markayash]

They are rated differently in that capacity. The filter you linked to was a 200 sq ft cartridge and among the smaller ones for your pool. If you go the cartridge route get the biggest you can, or close enough like the 500.

I second that, if you get a cartridge filter buy the biggest you can afford and have room for.
And shop around, amazon and ebay both seem to have a lot better prices than a local pool store.

 

[Newdude]

Where does the 500 come from for a cartridge filter? According to Pentair the 200 should be fine for flow. Does it have to do with cleaning frequency?

Yes. Exactly that. Most of them will work fine. But Pentair could give a hoot if you have to clean them every 3rd week (and learn to hate them). In good times a 200 sq ft would work ok for you, you would just be cleaning it 60% more often. If you had a problem and had to Filter out 35k gallons worth of algea it would be time consuming on several levels.

 

[Newdude]

Newdude, sorry I wasn’t thinking. Obviously 500 sq ft is ridiculous for a sand filter.

It’s confusing as heck sometimes when all these #s say 200 for example but are not the same. Pounds don’t equal sqaure feet but a different amount of pounds of sand can filter like X amount of square feet......... Meh. Pick a style of the big 3. There are a bazillion of each in the wild, and an equal amount of clean pools. Go as big as you can no matter the style.

*edit*. Someone with 8k gallons at some point reaches overkill. Someone with 35k gallons won’t.