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?



Yes, please post your results.

(And, if you haven't already, grab the manual, etc from here: Pro-Grid™ Vertical Grid

[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:


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