New DE Filter Owner

[Piney]

Greetings--

NEw owner of older pool-- THis one has a DE filter. Our pervious house had a sand filter on the pool.

From what I understand, when one backwashes a DE filter, some of the DE flows out, thus requiring a replacement.

QUESTIONS--

1) How does one determine the correct level of the DE media in the filter ? I have no idea if it was correct when we bought the house.

2) How does one determine a replacement amt of media after backwashing ?

3) What is the criteria for time to backwash ? period of time or pressure increase (like my sand filter) ?

4) How long does one backwash a DE Filter ? I"d watch the sight glass on my sand filter and run it for a couple of minutes after it ran clear.

 

[waste]

Sorry about the weird way this is presented, I'm not verry good with the computer Welcome to TFP!! The links provided below should help you - if you have any further questions, I'll be here to answer/ clarify
Location: central ct

PostPosted: Wed Jul 18, 2007 2:39 pm Reply with quote Edit/Delete this post

I'm not sure that anyone has actually realized that it's taken me ... quite some time but here are some links to PF on what I've suggested for DE filters

http://www.poolforum.com/pf2/showthread.php?t=7501
http://www.poolforum.com/pf2/showthread.php?t=6811
http://www.poolforum.com/pf2/showthread ... #post22431
http://www.poolforum.com/pf2/showthread.php?t=2562
http://www.poolforum.com/pf2/showthread.php?t=2261

 

[waste]

It's funny that it won't work for you, when I click on any of them, the page appears -- anyone have any ideas???

 

[Titanium]

waste,

The links you posted are working for me.

Titanium

 

[JasonLion]

PoolForum.com can not be accessed from many places outside of the US. The links work for me, but for many people outside of the US they don't work. I remember this same information getting posted here but I can't seem to find it right now.

Here is a little of what waste wrote over at PoolForum.com:

Put the multiport on backwash, and watch the sightglass for ~clear.
Rinse the filter till it is ~clear.
Repeat until the 'backwash' cycle is ~clear and rinse again. (~3-5 cycles)
Put it on filter for ~ 1 min. and do another backwash/ rinse cycle.
At this point, you've gotten ~80% of the de out, so only add 80% back in

try backwash/rinse/backwash/rinse/backwash/rinse before inserting the filter cycle, you'll get most of the stuff out before the filter cycle but running the filter cycle will open a few new channels in the remaining de and allow you to get a little more out with another backwash/rinse. After doing this add 80% as much DE as the manual says.

 

[waste]

Piney, sorry that the links won't work for you I've been meaning to write a post on DE filters, but haven't had the time to do it right My bad! Oh well, this will be good practice for when I finally get around to it.

First, I'm assuming that you have a multiport like the one that was on your sand filter.

When you go to backwash, turn off the pump when you change the valve positions (but you already knew that). The first thing to do is to make sure that the tank is full of water by opening the air relief valve until you get a steady flow of water. Then put the multi on backwash and watch the 'sightglass' until it is ~ clear. Then turn the multi to 'rinse' and run the pump for ~15 seconds. Then back to backwash ... just keep doing backwash/ rinse over and over until when you backwash for ~ 30 seconds, nothing more comes out. As long as the pool water isn't nasty (ie, algae filled or brown) run a ~1 minute filter cycle and then backwash/ rinse again. At this point, you've gotten all of the DE that you can out of the filter without taking it apart and thoroughly rinsing the grids, however - this is only about 80% of the DE that's in the filter - so when recharging the filter(adding more DE) only add 4/5ths of the recommended amount.

OK, now for the other questions:
The amount of De to add should be on the filter's label - if you can't read it because of the age, let me know the manufacturer and the height and girth and I can probably give you a good number for the size/ amount. The amount on the label is only for a fully clean filter, as per above, only add 80% if you've backwashed (ie, if the filter takes 6 lbs DE clean only add ~ 5 lbs after backwashing)

The easiest way to measure DE is with a scoop available at pool stores and other places that sell DE - most hold 1 lb but some only hold 3/4 lb. If you have a decent scale, you can weigh whatever you'll be measuring the DE with and then see how much DE it will hold (weigh it empty and see how much you have when full of DE, you may want to also see what it weighs ~ 1/2 full) While we're 'talking' about this, overcharging (putting in the full 'clean' amount of DE when the filter is still ~20% coated) will clog the grids after just a few backwashes (I've seen some that have ~ 20 lbs of DE in them - when the unit only is supposed to have 6 lbs ) and you won't be filtering efficiently. Conversely, not having enough DE in the filter can cause the fabric on the grids to clog up and the only way to fix that is to open the unit and manually clean the grids :x You should get used to manually cleaning the grids at least once a year - if you winterize the pool, doing it in the fall is what I'd recommend, that way you know you're starting out in the spring with a clean filter. Another reason to annually open the filter is to check to see if the grids need some chemical treatment - if the grids hold more than 1" of water for more than ~30 seconds, the fabric is clogged with either oils or calcium - at this point you want to soak them in a dilute mixture of TSP (tri-sodium-phosphate) or automatic dishwasher powder for a few hours. Then soak them in a dilute mixture of muriatic acid (something along the lines of 10 - 20:1) for ~5 hours. You'll know you're good if the water flows out fairly quickly when you pull the grids from the bath.

As for when to backwash, when the pressure gauge rises 8 psi over when the unit was 100% clean and properly coated with DE

You didn't ask, but I'll tell you anyway If you have 2 suction ports going (ie, skimmer and main drain or 2 skimmers), you can just add the DE to the skimmer, if you only have 1 skimmer, and no other suction, you need to premix the DE in a 5 gallon bucket before adding it.

I hope that this makes up for my laziness yesterday when all I did was link to some posts/ threads that you can't open If you need any more help, I'm more than willing to put in the time to answer your questions.

Please let us know how it goes :-D

 

[donaldm823]

DE refill only 80%-WHY???

Piney, sorry that the links won't work for you I've been meaning to write a post on DE filters, but haven't had the time to do it right My bad! Oh well, this will be good practice for when I finally get around to it.

First, I'm assuming that you have a multiport like the one that was on your sand filter.

When you go to backwash, turn off the pump when you change the valve positions (but you already knew that). The first thing to do is to make sure that the tank is full of water by opening the air relief valve until you get a steady flow of water. Then put the multi on backwash and watch the 'sightglass' until it is ~ clear. Then turn the multi to 'rinse' and run the pump for ~15 seconds. Then back to backwash ... just keep doing backwash/ rinse over and over until when you backwash for ~ 30 seconds, nothing more comes out. As long as the pool water isn't nasty (ie, algae filled or brown) run a ~1 minute filter cycle and then backwash/ rinse again. At this point, you've gotten all of the DE that you can out of the filter without taking it apart and thoroughly rinsing the grids, however - this is only about 80% of the DE that's in the filter - so when recharging the filter(adding more DE) only add 4/5ths of the recommended amount.

:-D

I have a 60ft3 DE Pentair filter (connected to a 2hp pump) that calls for a 6lb charge of DE. My backwash method is exactly as you describe, I however always added 6lb of DE material after the monthly backwash (never saw a 10psi increase) during the pool season. When I opened the DE filter at the end of this season (October), the DE drum and grids were empty of all DE material. This indicates that the backwash method was effective in clearing the DE container of all material. So why do you recommend only charging 80% of the initial charge??

 

[waste]

Don, it's great that your filter performs as it should :!: I speak in 'generalities' when describing this, if yours cleans fully when doing a complete backwash/ rinse... all the better for you I do however find it hard to believe that there isn't any DE remaining in the filter :? I open a few hundred of these every year and have never seen one completely clean, even when I do the best backwashing I can, there is always clumps of DE in some of the grids, especially at the top or bottom.

Either you do a better backwashing than I or you're missing some of the DE in the grids 8) Whichever, I hope your unit continues to work as you describe, but for most people - what I've said saves a lot of trouble

 

[donaldm823]

Don, it's great that your filter performs as it should :!: I speak in 'generalities' when describing this, if yours cleans fully when doing a complete backwash/ rinse... all the better for you I do however find it hard to believe that there isn't any DE remaining in the filter :? I open a few hundred of these every year and have never seen one completely clean, even when I do the best backwashing I can, there is always clumps of DE in some of the grids, especially at the top or bottom.

Either you do a better backwashing than I or you're missing some of the DE in the grids 8) Whichever, I hope your unit continues to work as you describe, but for most people - what I've said saves a lot of trouble

ok-thanks.

I did have a few "clumps" at top/bottom (maybe 2-3 golfball size), but this amount being so low I discounted it as "left behind". I do backwash every 30 days and usually my filter dp has only gone up 2 psi so it is clean when I backwash. Also I suspect my flow rate is high which helps the backflush since I have a 2hp pump for my size pool. But appreciate the advice, and confirmation that my backwash method "appears" to be working.

 

[Ohm_Boy]

PoolForum.com can not be accessed from many places outside of the US. The links work for me, but for many people outside of the US they don't work.

PoolForum.com cannot be accessed from my house in Katy Tx, either, since Comcast took over from Time Warner. I can't reach poolsolutions.com either.
I do not know if it's an issue with Comcast blocking PoolForum.com/PoolSolutions.com or if Ben set them up to block accesses that happen to come from us. Either way, I can't get to them unless I use a proxy server, like proxify.com

 

[waste]

FWIW - I recently switched over to comcast and have no trouble getting to polforum

 

[Ohm_Boy]

Yeah, I don't think it's a Comcast policy, or anything like that, but I assume it has something to do with the circuit routing somehow, and it probably makes my traffic end up on a network that Ben blocked. Ben hosted his own servers, programmed his own 'bad robot' traps, and did his own network security maintenance. He seemed to be pretty savvy with Apache, TCP, DNS and programming languages like PHP, and he was well-versed on intrusion attack methods, so there's no telling what he set up or blocked, nor how. Since Ben is no longer actively making any maintenance changes, I doubt his servers handle changes to the internet backbone as well as they should.

Like I mentioned, I can get there via a proxy, and unlike SOCKS based proxy servers, proxify.com is HTTP-based, so there are no settings to manage. Just go there, type in the target web address, and you're there.

 

[Piney]

Greetings--

Thanks for all the info folks!!

A couple more questions--


How does one tell if the filter grids are damaged or in need of cleaning/upplugging ? My guess is that there is little or no DE left, as I had no idea I needed to add a significant amt. after backwashing. Remember-- I'm a former sand filter owner.....

Why in the world would one want to use a DE filter ? From everyone's comments they appear troublesome maintain and fairly fragile, being easily plugged/damaged ? I hadnt heard these type of comments about sand filters.

Thanks again folks !!

 

[JasonLion]

DE filters out smaller particles than sand filters can, which makes them worth some extra effort to some people.

You can tell that the grids are damaged because DE will get through the grids and into the pool. There is no obvious way to tell if the grids need cleaning. The filter pressure will go up more quickly after a backwash when the grids are dirty, though there are other things that might cause that. Generally it is probably worth cleaning them once a year just in case.

 

[waste]

Don, it's great that your filter performs as it should :!: I speak in 'generalities' when describing this, if yours cleans fully when doing a complete backwash/ rinse... all the better for you I do however find it hard to believe that there isn't any DE remaining in the filter :? I open a few hundred of these every year and have never seen one completely clean, even when I do the best backwashing I can, there is always clumps of DE in some of the grids, especially at the top or bottom.

Either you do a better backwashing than I or you're missing some of the DE in the grids 8) Whichever, I hope your unit continues to work as you describe, but for most people - what I've said saves a lot of trouble

ok-thanks.

I did have a few "clumps" at top/bottom (maybe 2-3 golfball size), but this amount being so low I discounted it as "left behind". I do backwash every 30 days and usually my filter dp has only gone up 2 psi so it is clean when I backwash. Also I suspect my flow rate is high which helps the backflush since I have a 2hp pump for my size pool. But appreciate the advice, and confirmation that my backwash method "appears" to be working.

I was finally able to find this post again and want to comment on the discrepency between my awesome advice and Don's experience :lol:

Don is backwashing when the psi rises 2, while I say that backwashing needs to be done after a rise of 8 psi. In the process of raising the psi, the DE is getting filled or clogged up with the fine debris it is supposed to catch. The more congested the layer of De is, the harder it is to fully 'backwash'. As his has such a small amount of congestion, he's washing much more than 80% out (and probably with fewer 'backwash/ rinse' cycles). I know he's using more DE than my method would over the course of a season... the question is whether he's loosing more or less treated pool water ($ for water replacement and chems) -- and I don't know that answer My gut feeling is that it all sort of equals out financially.

Any thoughts :?:

 

[donaldm823]

Don, it's great that your filter performs as it should :!: I speak in 'generalities' when describing this, if yours cleans fully when doing a complete backwash/ rinse... all the better for you I do however find it hard to believe that there isn't any DE remaining in the filter :? I open a few hundred of these every year and have never seen one completely clean, even when I do the best backwashing I can, there is always clumps of DE in some of the grids, especially at the top or bottom.

Either you do a better backwashing than I or you're missing some of the DE in the grids 8) Whichever, I hope your unit continues to work as you describe, but for most people - what I've said saves a lot of trouble

ok-thanks.

I did have a few "clumps" at top/bottom (maybe 2-3 golfball size), but this amount being so low I discounted it as "left behind". I do backwash every 30 days and usually my filter dp has only gone up 2 psi so it is clean when I backwash. Also I suspect my flow rate is high which helps the backflush since I have a 2hp pump for my size pool. But appreciate the advice, and confirmation that my backwash method "appears" to be working.

I was finally able to find this post again and want to comment on the discrepency between my awesome advice and Don's experience :lol:

Don is backwashing when the psi rises 2, while I say that backwashing needs to be done after a rise of 8 psi. In the process of raising the psi, the DE is getting filled or clogged up with the fine debris it is supposed to catch. The more congested the layer of De is, the harder it is to fully 'backwash'. As his has such a small amount of congestion, he's washing much more than 80% out (and probably with fewer 'backwash/ rinse' cycles). I know he's using more DE than my method would over the course of a season... the question is whether he's loosing more or less treated pool water ($ for water replacement and chems) -- and I don't know that answer My gut feeling is that it all sort of equals out financially.

Any thoughts :?:

My pool builder (Anthony & Sylvan) recommended a DE backwash at 10psi pressure rise OR once every 30 days/4 weeks whichever comes first. That has been the only reason I backwash every month. I am pretty much a pragmatist when it comes to my pool-"whatever works". 6lb of DE is not that much for 1x per month ($6.00 per change) and the amount of water (approx 200gal) is also small for the backwash cycle I need every month. The one time I tried to go with the 10psi only criteria, I ended up with pollen issues in the water which later translated to a high chlorine demand which turned out to be lots of money.