Filter sizing?

[stlbill]

Hi folks:

I have a 19,000 gallon in-ground pool with a 1.5 HP 70 GPM pump. The chart on In The Swim states I should get a 36 ft^2 DE filter. If I can afford a 72 ft^2 DE filter is there any harm that could result?

[PoolDoc]

It's what I'd do -- your filter will go longer between cleanings. The only downside is that it will not backwash as well -- but my experience is that DE filters NEVER backwash all that well, and that it's usually better to break them down and clean them by hand if possible, at least 1x per season.

[stlbill]

Hi PoolDoc:

I purchased a Hayward DE7220 this weekend. It will be a few weeks before opening. I'll post my findings for the benefit of anyone else considering a filter change.

Thanks!

-Bill

[PoolDoc]

This one?

http://www.hayward-pool.com/images/pools/products/large/ProGridVertDE.jpg

Yes, please post your results.

(And, if you haven't already, grab the manual, etc from here: Pro-Grid™ Vertical Grid (http://www.hayward-pool.com/prd/In-Ground-Pool-D-E-Filters-Pro-Grid-Vertical-Grid_10201_10551_13509_-1_15516_13502_I.htm)

[stlbill]

No. This is a picture of a Hayward cartridge filter. I have a DE7220 de filter. Actually I have an older 200 ft^2 Hayward cartridge filter connected to the pool and a Hayward de filter waiting to be installed.

[PoolDoc]

Then, this one:
http://www.hayward-pool.com/images/pools/products/large/ProGrid_2.jpg

That's a Pro-Grid; the first one is a Pro-Vertical Grid, from this page: http://goo.gl/Bf4ni

[stlbill]

Hi PoolDoc:

Yes the second picture more closely resembles the filter I purchased. Just take away the push-pull valve and replace it with a 6-way model and it's perfect.

I realized the first problem with switching from cartridge to de filters today. The cartridge filter has the backwash outlet on the other side. On a cartridge filter you go from pump to filter and filter to pool. On a de filter you go from pump to valve, valve to pool and valve to backwash. All three connections are on the same side of the de filter and the valve extends about 12" away from the filter. The input and output on the de filter are exactly the same height as the cartridge filter, but the valve changes things. This would be no issue if I have above-ground pool style flex hoses, but my pool is all pvc hard plumbing.

This is not going to be a diy project any more. At least not for me. Fortunately the people I bought the house from gave me the name of the pool builder. I talked to the pool guy today and he gave me a very reasonable estimate and installation time.

More to follow...

[PoolDoc]

For what it's worth, the first picture I put up IS a DE filter.

Manufacturers use the same case for different filter types, when they can. StaRite puts all three types of filters (sand, DE, cartridge) into the same case, in their System3 filters.

My point is, you may want check carefully, and see if there is a DE filter that will fit, and not be so difficult to plumb.

[stlbill]

Hi folks:

My pool builder installed the DE and removed the cartridge filter today. Installation looks clean. I'm planning to open in late April or early May, but if this recorrd-breaking warm weather keeps up we might open before that.

Here is to hoping I can see a difference with DE. My pool builder doesn't think I will. I hope he is wrong...

Thanks for your advice PoolDoc!

[PoolDoc]

Let us know how it goes, please!

Ben

[stlbill]

Hello everyone,

Well, I am about one-third of the way into my second season using the big DE filter. I love it! My cartridge filter did not have a multiport valve. The multiport valve alone is worth the change! At opening this year I topped off the water level and vacuumed all the Winter junk directly to waste. When I had removed all of the big stuff I refilled to the proper level and put the multiport in recirculate to get my water balanced. Then I shocked it, flocked it and vacuumed all the dead stuff to waste. Then I turned the multiport to filter mode and made it truly sparkle. Vacuuming to waste and having an over size filter means I only have to clean this filter twice a year: Once after opening and again at closing. Cleaning it at closing is just for effect. The pressure does not dictate it. If I lived in a place that does not require winterizing the pool I think it would go most of the winter months without issue.

Remember the 72 ft^2 filter has tall grids? The only challenge I am having is finding a container large enough to fit the DE grids in for soaking. I searched all over for a Rubbermaid 50 gallon trash can that was deep enough and had no metal parts. It lasted one cleaning cycle. The second time I filled it up with water deep enough to cover the grids and a big rupture formed near the wheel axle. These "Build For Life" Rubbermaid cans are obviously not built to be full of water.

I am now looking for other plastic barrels rated to not rupture when full of water deep enough to submerse the grids. Most 55 gallons are just 36" deep and these grids need more than 40" to submerge.

Another option might be to soak the bottom half of the grids for 12 hours, turn them over and soak the other half. Not as good, but maybe it will work in a shallower container. Comments appreciated!

Thanks,
Bill

[PoolDoc]

Another option might be to soak the bottom half of the grids for 12 hours, turn them over and soak the other half. Not as good, but maybe it will work in a shallower container.

Tha's what I'd do. All of the larger plastic containers I've see would be VERY large, and expensive, both for the container, and the cleaning solution.