How do folks backwash?

[PoolDoc]

Looks like that manual is only partially readable? And, I assume you do NOT have the associated separation tank?

Still, with my limited experience with residential pressure DE filters (most of the DE filters I've worked with were giant commercial vacuum DE filters), it's worthwhile to periodically break down the filter. Unlike sand filters, backwashing DE filters only seems to work partially. Full cleaning requires opening the filter, ESPECIALLY if you haven't done so in a while.

[SL Dan]

I've done it 4 or 5 times so far this year. And right, I don't have the separation tank. Until I DL'ed that manual, I didn't even realize there was a separation tank. This filter was gotten by our last pool man.

But I'm wondering what most people who have DE filters do with waste water/DE/algae when they backwash.

[PoolDoc]

It sounds like you are looking for a discussion on the topic; there's probably enough traffic on TroubleFreePool for a discussion. Not sure about PoolSpaForum. You may want to register and post your ? on TFP.

[SL Dan]

Okay - I didn't know about that site. This place is my go-to. Thanks.

[PoolDoc]

Thanks, but there's a fair bit of traffic here from Google searchers, but very little from registered members . . . so not much new discussion. That's not something that will change before next spring, for a variety of reasons.

[SL Dan]

Hi Ben,

Can you explain why I should get such a large filter for a 20,000 gallon pool? I'm about to pull the trigger on something.

[SL Dan]

Oh, and because of the DWP rebate program, I'm going to install a Pentair variable speed pump.

[PoolDoc]

• All filters function better with low flow rates per sft of filter area. This is ESPECIALLY true with sand filters.
• All filters run longer between cleaning with low flow rates.
• High flow rates tend to damage filters. High flow = high differential pressure which KILLS filter cartridges, especially modern 'high-capacity' cartridges with pleats that are too close together. High flow may damage DE membrane support grids. High flow WASHES SAND OUT of the filter during backwash, and PUSHES DIRT THROUGH the filter during operation on sand filters.
• It is still possible to develop high differential pressure, across the media, with oversize filters but it's much less likely.

Is that enough? If you need more, you'll have to wait till later this weekend.

By the way, REGARDLESS of filter type or size, you need a WORKING pressure gauge to monitor filter ops properly.

• NO FILTER should operate at over 30 psi absolute (unless it's the new-ish Pentair high-pressure sand filter).
• NO FILTER should operate at more than a 7 or 8 psi pressure rise (clean to dirty). Cartridge filters should be cleaned at a 5 psi rise (old style) or 3 psi rise (new style with pleats too close).

[SL Dan]

Thank you.

If there's more to say, of course I want to know.

[SL Dan]

BTW, I've ordered the recommended filter, the Hayward C3070, and a Pentair Superflo VS. They'll be installed next Friday, September 6th.