Is it necessary to backwash a DE filter every 30 days?

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atccf

atccf

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May 10, 2019
39
Winchester, VA
Pool Size
25800
Surface
Plaster
Chlorine
Salt Water Generator
My PB recommends every 30 days or 25 psi whichever comes first. With fresh DE in the filter, my pressure is 18 psi and after 35 days my pressure is just under 20 psi. It seems to me that it's a waste of DE and water to backwash for less than a 2 psi increase. Is there a scientific or safety reason for the 30 day "requirement"? Thanks in advance for any advice!
 
There are plenty of owners, if you told them "when pressure rises by X amount," they would say sure, and promptly forget it. Say 30 days, and that gets put on their mental or actual calendar. It's more likely to actually get done if they give a time and not just a pressure.
 
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Craig,

I have a couple of rent house pools that have DE filters.. I keep hoping they will die, so I will be "forced" to replace them with large cartridge filters.. :mrgreen:

I never backwash anymore.. I basically clean them about every 6 months.. I can do this because I run VS pumps at low RPMs so my filter pressure is usually below 4 or 5 lbs. I removed the MPV from both of them which is working great for me.

The point being that backwashing every 30 days is beyond ridicules in my opinion.

The 25% pressure increase is a great guideline that works for most pool owners.. I find that a better indicator for me is the "feel" of the return water.. As the filter gets dirty, you can feel the return flow decrease. As long as I have good return flow, then I don't worry about the filter.

Thanks,

Jim R.
 
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Jimrahbe said:
Craig,

I have a couple of rent house pools that have DE filters.. I keep hoping they will die, so I will be "forced" to replace them with large cartridge filters.. :mrgreen:

I never backwash anymore.. I basically clean them about every 6 months.. I can do this because I run VS pumps at low RPMs so my filter pressure is usually below 4 or 5 lbs. I removed the MPV from both of them which is working great for me.

The point being that backwashing every 30 days is beyond ridicules in my opinion.

The 25% pressure increase is a great guideline that works for most pool owners.. I find that a better indicator for me is the "feel" of the return water.. As the filter gets dirty, you can feel the return flow decrease. As long as I have good return flow, then I don't worry about the filter.

Thanks,

Jim R.
Click to expand...
Thanks for the insight. Our pool is still relatively new and I'm still trying learn more ways to cut down my maintenance time so I can spend more time enjoying the pool.
 
With a VS pump running at a slow speed and using hairnets in my skimmers, I have found that I can get by with a couple cleanings of my DE filter each year. My son who has a pool half the volume, VS pump and a huge cartridge filter, uses hairnets and only cleans filters once a year. Hairnets work wonders. They remove 80-90% of the debris that would otherwise clog the filter.
 
When I had a DE filter, I found backwashing simply was a waste. I didn't have much debris, so I just did a complete disassembly and cleaning every 12-18 months. TFPC and skimmer hairnets really extend your filter cleaning intervals.
 
atccf said:
My PB recommends every 30 days or 25 psi whichever comes first. With fresh DE in the filter, my pressure is 18 psi and after 35 days my pressure is just under 20 psi. It seems to me that it's a waste of DE and water to backwash for less than a 2 psi increase. Is there a scientific or safety reason for the 30 day "requirement"? Thanks in advance for any advice!
Click to expand...
I waited to backwash until my flow started dropping off (it was easy to see the skimmers weren't working well anymore). That said, this corresponded to between 25% and 50% increase, so the rule of thumb seems to work.

I will note that my days of having to do this every 30 days also corresponded to pre-TFP and having not nearly enough chlorine for my CYA. My water was always crystal clear, but clearly there was an algae problem on the verge of breaking out.

Jimrahbe said:
Craig,

I have a couple of rent house pools that have DE filters.. I keep hoping they will die, so I will be "forced" to replace them with large cartridge filters.. :mrgreen:

I never backwash anymore.. I basically clean them about every 6 months.. I can do this because I run VS pumps at low RPMs so my filter pressure is usually below 4 or 5 lbs. I removed the MPV from both of them which is working great for me.

The point being that backwashing every 30 days is beyond ridicules in my opinion.

The 25% pressure increase is a great guideline that works for most pool owners.. I find that a better indicator for me is the "feel" of the return water.. As the filter gets dirty, you can feel the return flow decrease. As long as I have good return flow, then I don't worry about the filter.

Thanks,

Jim R.
Click to expand...
You're more patient than me. I ditched my tiny DE filter and went with the biggest quad cartridge Pentair makes (I think). I still can't figure out what I'm supposed to do with my old DE filter...
 
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