I am NOT asking any pool supply company (and that’s who answers questions on pool forums, too) for the same reason that I came here to fix my goethermal system after the so-called experts failed miserably. Thanks to the SDMB, my geothermal system is rocking. Thanks to ‘experts’ and geothermal companies out there, well '‘f-ck them’ sums it up.
Now to the pool… my DE pool filter… I want to know this:
When backwashing, is this also a dump of all the DE? I need to add a full dose (or so) of DE when I complete a full backwash/rinse cycle?
I’ve had silica sand filters my whole life (if this background info helps). I backwashed and then rolled up the hose. Presto.
Now… I must backwash, find the DE capacity on the filter, then add DE to the nearest skimmer?
THANKS, Dopers. Feel free to add in any other info that might help. Pool chemistry I aced long ago; it’s simply the workings of a DE system that I want to know about from non-biased people.
That’s what we do. We bump and flush, bump and flush, until the water starts coming out clear. Then we close it up and refill with the full amount of DE through the skimmer.
I never add the full amount.
My filter holds 3.5 lbs. I only add 2.5 lbs (coffee can measure) after a backflush. At the end of the summer, when it’s time to clean the filter, there’s always a lot of DE that doesn’t get backflushed out.
The goal of backflush is to flush 100% of the DE off the filter carriers. Which means IF you achieve that goal, THEN you need to add a full dose of DE.
As **PaperBlob **says, the idea is to backflush as many times as necessary to get clear backflush water which means all the old dirty DE is gone.
You could decide to do half-ass backflushes more often & replace only a half-dose of DE, but pretty quick you’ll end up in the staate where you have no idea how much DE is actually adhering to your filter carriers. They might be half clear, or half totally gunked up, or even both.
Pretty much, the DE is the only real filtering; the rest of the system is so course that it’ll trap sand and leaves and that’s about it. Any removal of microorganisms and fine silt come from the DE.
Once the DE gets glopped up, it can turn into a growth medium. Just like using a really nasty unwashed dishrag for months becomes a way to spread bacteria & food slime onto freshly used but mostly safe dishes, rather than a way to get freshly used dishes clean.
Reading between the lines I suspect you’re hoping to avoid the expense of replacing DE so often. Better to do a thorough flush job less frequently than a poor job more frequently.
Depending on how bio-active your local enviroment is, and how good you are about maintaining chemical balance, you may be able to go 2x to 4x as long between backflushes as the pool store selling DE recommends. You’ve got nothing to lose by trying it out.
Not looking for any cheap way out. I just wanted facts. Some ‘experts’ tell you one thing to see you spending more, and some give advice that is the cheap way out and yields poor results.
So, I’ll be buying DE and doing full backwashes. I know about the coffee can thing and to be careful not to overfill the DE level. Keep ya posted.
Quick question if you don’t mind since the main’s been answered… if you switch to a salt system, don’t you still need to maintain your D.E. filtration system? I inquired about making the switch and was told they could just cut out the DE and put the salt (Na Ion generator?) in it’s place. This made no sense to me as I understood the DE did nothing regarding chemicals and the salt does nothing regarding filtration.
Would or would not those two work in collaboration?
From what I know, you can filter w/ these options:
DE
Sand
Cartridge
And the effectiveness is in that order (prob with exceptions, but that’s a guide. I’ve seen huge pools use cartridges)
Salt is about sanitizing. The salt, and the chlorine it’s converted into, sanitize the water.
I don’t think you can rip out a filtration system because you have a saltwater pool. I have a saltwater pool and all the saltwater pools I’ve seen have filtration systems (usually DE). I had a sand filter in my previous home and almost made it a salt setup, in which I would have just added the salt system (chlorine generator, etc).
I wouldn’t. I’ve heard of people adding DE to sand filters, but this is a way of clogging up a filter, which really makes it an even better filter, but can reduce flow too much and gunk up other bits.
