Filter Help

[jmastron]

We recently bought a house with a pool; I think I have the basic chemistry under control thanks to this site, now moving on to address some of the equipment oddities, particularly the filter (and later I will have some skimmer/main drain questions for another thread).

Basics: 21000(est) gallon pool, plaster finish, likely built in the late 50s/early 60s, probably resurfaced more recently. 2 pumps: a 3/4hp main pump (circa 2005 from a phone call to AO Smith) and 3/4hp boost pump (circa 2011) connected to a relatively new jet on the side with a Polaris pressure side cleaner. Seems to keep the bottom pretty clean (when I remember to zip the bag, doh!).

My questions are about the filter -- DE, of unknown spec and age. The actual container (not including stand) is green metal, 24” high and 18” in diameter. It has a “Leslie’s Diatomaceous Earth Filter” label, but all of the actual info fields appear to be blank (faded off with age?). Some rust all around the filter, and it (or something nearby) is leaking. There is a backwash valve hard-piped underground to the street (to a drainage ditch that flows to a creek then to the river). All of the house drains and sewer cleanout are around the front, around 200’ away.

Pictures:

(view of the pressure gauge from the back)

All of this is under a very low structure that was clearly built on top of the equipment after it was installed. The roof is permanently installed, and there are a couple of access doors not quite in the right place (I had to reach my phone in to get a picture of the pressure gauge). I’m guessing the filter hasn’t been opened since then. I’m going to take the structure apart, at least opening up the roof. Unfortunately all of the electrical is (badly) done on one of the sides, so I’ll need to keep part of it for now.

The “hut”: http://tinypic.com/r/dbnn2a/8

So, finally, the question:

I’m hesitant to even try to backwash this thing -- is there a simple way to figure out/estimate how much DE to add? Any idea how old it is? The guy at Leslie’s said it was so old he didn’t know, suggested opening it up to measure the grids. I’m afraid to do that for fear that more things will get broken/contaminated and now be an emergency repair.

I’m inclined to just replace the whole filter now, most likely with a cartridge filter (mainly to avoid the backwash issues), and have read some about sizing etc. I was planning to do the installation myself if possible. Are there any gotchas I should know about? Is it as simple (hah!) as removing the multiport valve and repiping the pump/filter outputs/inputs directly? Should I expect any issues/changes with the water if I do this? Or am I looking at this wrong and this one is not end-of-life and worth saving?

 

[jblizzle]

Welcome to TFP!!!

Please use the "IMG Code for Forums & Message Boards" to the left of your pictures in Tinypic when you paste the link into the forum message. That will allow them to show up automatically without clicking a link.

 

[SunnyOptimism]

Just adding more DE to the filter will do nothing except clog it up further and raise your water pressure. You have to backwash a DE filter or else you end up with a thick layer of cement on the grids. Without any kind of serial number it's hard to know how much DE it will take to recharge. If you do open it, you should backwash first to clear all the gunk off the grids.

What reason do you have for not backwashing?

Also, while you are right that you don't have to backwash a cartridge filter, they do still require routing cleaning by disassembling the unit and pulling the filters. From your pictures it doesn't look like you have a whole lot of room to work in with the "hut" built around your equipment like that. A good sand filter, while not achieving the same particulate size filtration as a cartridge, might be a better fit for low maintenance as the backwashing of a sand filter doesn't require you to recharge with anything (but you can always add DE to a sand filter if you like...).

 

[jmastron]

Just adding more DE to the filter will do nothing except clog it up further and raise your water pressure. You have to backwash a DE filter or else you end up with a thick layer of cement on the grids. Without any kind of serial number it's hard to know how much DE it will take to recharge. If you do open it, you should backwash first to clear all the gunk off the grids.

What reason do you have for not backwashing?

Also, while you are right that you don't have to backwash a cartridge filter, they do still require routing cleaning by disassembling the unit and pulling the filters. From your pictures it doesn't look like you have a whole lot of room to work in with the "hut" built around your equipment like that. A good sand filter, while not achieving the same particulate size filtration as a cartridge, might be a better fit for low maintenance as the backwashing of a sand filter doesn't require you to recharge with anything (but you can always add DE to a sand filter if you like...).

Thanks for the reply; I apologize that I wasn't clear -- I understand that I don't just add DE without backwashing first. I would like to backwash, and even have a box of DE ready to go, but:

1) I don't know how much DE to put in after I do that, as all of the label info is blank and nobody locally has been able to identify it. Is there a "safe" amount to add without knowing that won't make things worse than they are today? Only owned the place for about a month, so I'm not sure when/how it was last done.

2) The backwash drain is piped straight to a drainage ditch that feeds to a creek that flows to a major river, which is explicitly not allowed here. I could probably just pretend to not know that for now, but would need to fix that going forward. The sanitary sewer and all of the house drains are very far away on the other side of the house, probably 200' and a fence with no gate in the way. I've seen the backwash hoses, but that seems like a bit of a pain to have to set up each time.

Given that it seems to be rusted and leaking, I was prepared to just change it out if it's as old as it looks. I'm open to replacing with a sand or another DE filter, but will still have the backwash drain issue. I don't think I'd mind occasional cleaning.

And I will be removing the roof and most of that "hut" altogether and building a higher structure (perhaps), so access won't be an issue once my Sawzall gets warmed up I'm not sure what they were thinking with that thing.

 

[SunnyOptimism]

Hmmmm, you can probably get away with backwashing into the creek because the installation of that filter is likely older than the environmental regulation therefor you could claim to be grandfathered in. But, as soon as you upgrade the equipment, you'd lose that argument.

But I get it, you're just a good ole CA tree hugger at heart (joking)

So, here's my $0.06 worth of opinions -

1. You can add a sand filter and still use that backwash pipe since bachwashing a sand filter doesn't involve DE.

2. You can install a DE filter but use cellulose fiber instead (not as good as DE but better than just a straight cartridge) and still use that backwash line. Also, you could use DE with a separation tank on the backwash line and then dispose of the DE in trash.

3. Go cartridge filter and install it knowing that you'll need to take it apart for cleanings.

#1 & #2 assume that you CA crazies don't have any regs against backwashing pool water. If CA environmental regs treat pool water as "treated water" then your hosed (no pun intended) because "treated water" sometimes isn't even allowed down sewer drains.

 

[jblizzle]

I am not sure I would go so far as to say that DE is better than the cellulose ... I just switched and notice no real difference. And there are no health or environmental concerns with the cellulose.

 

[SunnyOptimism]

I am not sure I would go so far as to say that DE is better than the cellulose ... I just switched and notice no real difference. And there are no health or environmental concerns with the cellulose.

I've heard both claims - just as good and a little bit worse. Unfortunately, without any objective data to point to, it's all anecdotal. And, as the old saying goes, "'data' is not the plural form of 'anecdote'."

But I'm not at all against using cellulose especially if it means getting a person past some environmental regulations (like separation tanks, etc).

 

[jmastron]

Hmmmm, you can probably get away with backwashing into the creek because the installation of that filter is likely older than the environmental regulation therefor you could claim to be grandfathered in. But, as soon as you upgrade the equipment, you'd lose that argument.

But I get it, you're just a good ole CA tree hugger at heart (joking)

So, here's my $0.06 worth of opinions -

1. You can add a sand filter and still use that backwash pipe since bachwashing a sand filter doesn't involve DE.

2. You can install a DE filter but use cellulose fiber instead (not as good as DE but better than just a straight cartridge) and still use that backwash line. Also, you could use DE with a separation tank on the backwash line and then dispose of the DE in trash.

3. Go cartridge filter and install it knowing that you'll need to take it apart for cleanings.

#1 & #2 assume that you CA crazies don't have any regs against backwashing pool water. If CA environmental regs treat pool water as "treated water" then your hosed (no pun intended) because "treated water" sometimes isn't even allowed down sewer drains.

I don't really consider myself a tree hugger (my wife might be though , but I try not to intentionally do things that can cause problems, and this storm system really does go fairly quickly to the river.

And yes, the "CA crazies" do have regs against pool water going into the storm sewer system, DE or not -- actually, from my searches, many places, most of them not in CA, have similar rules. Here, they basically want only:

1) Backwash water down the sanitary sewer system, but via a settling tank (that's mentioned with permanently plumbed connections, so may not be required for a rolled out hose to the cleanout)
2) Draining non-backwash water to the storm sewer, but only within a pH range and if it's only had chlorine and acid in it, and then only after letting chlorine dissipate to 0.01ppm over 3-5 days.

I can justify being ignorant about where the drain goes with the current filter, but if I'm installing new I really want/need to do it right. So unless we're going to be disappointed with the performance of a cartridge filter, will most likely go that way, and from research here will go as big as feasible to minimize the cleaning frequency. I'm really just debating whether to try to eek out a few more (months, years?) out of this filter, meaning figure out how to backwash+add DE to it, or to in clear conscience declare it "old" and replace it right now.

 

[SunnyOptimism]

Wow, seriously tree-friendly regs. Thankfully I live outside the Tucson city limits in Pima County which means I get to use my backwash to water the plants, DE or no DE, pH and chlorine be darned!!

(FC actually dissipates quite rapidly in the first few inches of soil and has almost no effect on plant roots, so that particular reg is utter nonsense....but hey, bureaucrats have to have something to do....)

Given your situation, I'd agree that a cartridge filter makes the most sense. Over sizing a bit is always a good idea too.

As for when, heck, I say if you have the time and money then do it ASAP and forget the aggravation of trying to figure out that old equipment. In fact, it would probably be best to just get it all done at once (filter, new electrical, rework the equipment pad, etc). Do it at the end if the season so you can be ready to go the following spring.

So for my Pentair QuadDE 100 filter, the instructions say to use 10lbs of DE on a fresh start up. That's like 20 coffee cans worth. When I recharge from a backwash, I only use half that amount (and sometimes less). Without knowing your grid size (sq ft area), it's hard to say what will work for you.

 

[jmastron]

Okay -- I wasn’t sure if it was appropriate to keep semi-related followups in the same thread, or to start a new one; apologize if I have it wrong.

Decided to just replace the filter, as this really isn’t catching much debris and the pressure is pretty high -- I ordered a Pentair CCP420 and am planning to do it myself this weekend. It sounds like the CCP320 would also have been sufficient (approx 21000 gallon pool), but it was $90 more for the 420, and it seems that guidance here is that bigger is better if affordable. I had looked and gotten a quote on a Sta-Rite (more expensive), but the Clean&Clear seems to be a bit easier to maintain (and not as silly looking

Any cautions about this particular filter or the craziness of my plan to install this myself? Consider myself pretty handy, and have done some copper and pex plumbing, but not much with PVC. Here are my thoughts:

- I will remove the multiport valve and old filter completely

- I plan to plumb in the existing drain to the street for “just in case” (it is legal here to drain to the storm sewer if chlorine is allowed to dissipate over a few days first and a few other conditioins like testing pH). Can I do that simply using a tee and 2 ball valves, one on the leg going to the drain, and the other on the leg going to the filter? I understand it would be bad to close both, but the same issue can happen if someone closes all return valves.

- Since the existing pumps and return/drain lines are 1.5”, I’ll just use 1.5”<->2” couplings before the filter, knowing that when the pump gets replaced more of the system would go to 2”, right?

Any thoughts, comments, suggestions, or warnings?

 

[SunnyOptimism]

Sounds like a plan. However, instead of using two ball valves to control flow, buy a Pentair or Jandy three way valve to select drain versus filter. Fewer PVC joints and it avoids the problem of dead-heading the pump. Another reason is that ball valves are not really good for pool equipment and eventually leak. Jandy-style valves are much more reliable.

Oh, and great choice on the C&C cartridge filter....bigger is definitely better!


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[jmastron]

Sounds like a plan. However, instead of using two ball valves to control flow, buy a Pentair or Jandy three way valve to select drain versus filter. Fewer PVC joints and it avoids the problem of dead-heading the pump. Another reason is that ball valves are not really good for pool equipment and eventually leak. Jandy-style valves are much more reliable.

Oh, and great choice on the C&C cartridge filter....bigger is definitely better!


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Thanks, good suggestion to use a 3-way valve; I'm hoping the Leslie's nearby carries them. I'm thinking I should use a 2" valve to be future-ready (the new filter and in the future the pump), even though that means another reducer down to the drain?

Is there a common/good way to add a hose bibb to divert some water to use on the lawn or elsewhere? It'd be yet another diversion choice, and I understand I can't send all of the water to a narrow hose bibb -- perhaps better to just get a separate pump to use with a hose if I ever need to; I can use it for other things around the house too.

 

[SunnyOptimism]

Thanks, good suggestion to use a 3-way valve; I'm hoping the Leslie's nearby carries them. I'm thinking I should use a 2" valve to be future-ready (the new filter and in the future the pump), even though that means another reducer down to the drain?

Is there a common/good way to add a hose bibb to divert some water to use on the lawn or elsewhere? It'd be yet another diversion choice, and I understand I can't send all of the water to a narrow hose bibb -- perhaps better to just get a separate pump to use with a hose if I ever need to; I can use it for other things around the house too.

This is a picture of a hose Bibb above my pump output -


This is a picture of a Pentair three way valve -



Get 2" or 2 1/2".



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[jmastron]

Interesting, so you basically get whatever the backpressure is from the filter out the hose (when the hose bibb is open, of course)? Or does that 3-way valve have an additional "off" position to restrict the flow enough to put more pressure (but not all) on the hose?

 

[jblizzle]

You can not run it all out of the hose without severely restricting the pump.

 

[jmastron]

You can not run it all out of the hose without severely restricting the pump.

Right, that's my understanding -- that's why I'm trying to figure out how to plumb it so I can get a decent flow through the hose with the rest going through the filter; I would think that just having the 3-way valve full-on to the filter wouldn't provide enough pressure on the hose.

 

[jblizzle]

You will get plenty of flow out of the hose right above the pump like in the picture ... lower resistance out the hose than through the filter and the rest of the plumbing.

 

[SunnyOptimism]

Gents,

That hose Bibb is only used when I want to drain off water from the pool without going through the hassle of a backwash. At normal pump speeds and after a fresh backwash, my system pressure is roughly 12psi and the best that hose Bibb can do with a 20ft standard garden hose attached is ~6 gal/min flow rate. There is no visible change in pressure when the Bibb is full open. So that Bibb really doesn't draw off that much water relative to what's pushed to the filter.

The three way valve in the picture is one if two valves in the suction side of the pump's wet head. That particular valve sets the fraction of water drawn from my skimmer/MD and the suction line that KreepyKrauly attaches to. Between that valve and the pump is another three way valve with automation that controls where the water comes from- pool or spa.

Sorry if the pictures were confusing.


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