Help with Quad DE

[Redshift]

I split this off from HERE so that the other thread is not cluttered. jblizzle

Hey everyone, fairly new to TFP but long time reader. Good thread on Quad DE. I've had mine since 2010 but am struggling with something that I figured you could advise me on.

My pool generally runs fine. I have roughly 17,000 gallons, salt and ozone system, in ground, Quad DE 60 filter.

When we have parties and high bather loads, the filter can go from "just cleaned" to "clogged" within the span of a few hours. I'm talking like literally I cleaned the filter using this method the day before and check the pressure gauge and then 2-4 hours after our party starts and everyone is in/out of the pool, it's clogged to past the "clean" mark on the pressure gauge and flow is almost down to zero.

I read elsewhere that you can run the Quad DE as a cartridge filter and not use DE so I tried that but even that gets clogged after a couple weeks and backwash doesn't seem to help much.

I bought new cartridges a couple months ago so that I could have spares at the ready (nothing wrong with the originals, just stained but they clean up nicely and are not broken or leaking) but my neighbor tells me that he thinks they are absolutely SUPPOSED to run with DE at all times or the grids clog up and now may need a serious chemical cleaning.

This behavior has me hating the filter with a passion and not sure what to do about it. I don't mind teardown and hosing off the grids every once in a while but I shouldn't have to clean the filter before AND after having friends over, should I?

Any advice or suggestions?

 

[JoyfulNoise]

Re: Guts of QuadDE Filter

I have never experienced that. What you're describing should not happen and leads me to think that the cartridges are somehow loaded up with organics. Did you ever acid wash the cartridges? Do you bathers use a lot of sunblock or tanning oils? The cartridges may need a chemical cleaning.

But I would say this - your neighbor is correct, you should NEVER run the filter without DE. The cartridges are a special polypropylene material that are designed to hold DE, they do not filter at all. Running without DE can damage them and load them up with debris.

 

[Jimrahbe]

Re: Guts of QuadDE Filter

Brian,

As Matt says.. this should not be happening!!!

My guess is that you are running your FC at 1.0 ppm and thinking that because you have an ozone system that is good enough. What FC level do you shoot for?

I'm curious at what speed your IntelliFlo is running when your filter gauge is reading in the "clean" area.

Tell us what your readings are...

FC
CC
pH
TA
CH
CYA

Thanks,

Jim R.

 

[JoyfulNoise]

Re: Guts of QuadDE Filter

Brian,

As Matt says.. this should not be happening!!!

My guess is that you are running your FC at 1.0 ppm and thinking that because you have an ozone system that is good enough. What FC level do you shoot for?

I'm curious at what speed your IntelliFlo is running when your filter gauge is reading in the "clean" area.

Tell us what your readings are...

FC
CC
pH
TA
CH
CYA

Thanks,

Jim R.

Good catch Jim!! I was so caught up in the mechanics that I totally forgot about the fact that a DE will clog up in less than a day if there's any algae in the water.

Redshift,

I would also perform an OCLT to see if there's a chemical/algae issue.

 

[Redshift]

Re: Guts of QuadDE Filter

Hi everyone, thanks for the responses!

I have been having issues with my salt cell and Cl levels. Has hit zero a few times with tiny algae blooms beginning in some areas. I'm talking 1mm at most and only on the tanning shelf. I believe I have those licked (new cell and new cable) but there still may be some issues with organics plus clogged filter media.

I actually aim for 2.0-3.0 but I agree with everything above. I think I need to acid wash the cartridges because that hasn't been done. Which procedure should I use for the Quad DE cartridges specifically?

My guests typically lotion up before swimming. We're talking 30-50 people. I think people are bad about letting the lotion dry before hopping in, which exacerbates things, but I also have a theory that those stupid spray-on sun blocks are partially to blame. I hate those darn things.

I will run outside in a few min and grab some readings and post back.

 

[Redshift]

Re: Guts of QuadDE Filter

As of this second here are the numbers. I don't know how relevant they are because this phenomena of the filter clogging up really quickly after high bather load has been going on for a while. It also looks like I may not have solved the salt cell issue after all.

FC 1.0 (I usually aim for 2.0-3.0 daily)
TC 1.0
CC 0.0
pH 7.8 (even after 7 years I still end up having to add acid about 1/2-3/4 gal per week (down from 1 gal per week last year and 2 gal per week before that) - I typically aim for 7.4ish but I am happy anywhere from 7.2-7.8 or so
TA 85
CH 270
CYA ~100

I have had pretty okay luck doing DIY maintenance but it seems like things are starting to get into areas I'm not familiar with. What do you guys and gals suggest? I'm very handy and want to take care of everything myself...this is just getting a bit stressful with other life demands at the moment.

 

[Jimrahbe]

Brian,

30 to 50 people is not heavy use, that is more like a Public Pool...

Check out this chart... [FC/CYA][/FC/CYA] With a CYA of 100 your very absolute minimum FC needs to be about 6 or 7... Our chart does not even go that high for SWCG pools.

This is why your filter is clogging so quickly.

What are you using to test you pool water??

If nothing else, I would use liquid chlorine/bleach to increase your FC before and after you turn your pool into a public playground. (I'm just jealous.. I don't think I know 50 people, total... )

Thanks,

Jim R.

 

[JoyfulNoise]

Re: Guts of QuadDE Filter

As of this second here are the numbers. I don't know how relevant they are because this phenomena of the filter clogging up really quickly after high bather load has been going on for a while. It also looks like I may not have solved the salt cell issue after all.

FC 1.0 (I usually aim for 2.0-3.0 daily)
TC 1.0
CC 0.0
pH 7.8 (even after 7 years I still end up having to add acid about 1/2-3/4 gal per week (down from 1 gal per week last year and 2 gal per week before that) - I typically aim for 7.4ish but I am happy anywhere from 7.2-7.8 or so
TA 85
CH 270
CYA ~100

I have had pretty okay luck doing DIY maintenance but it seems like things are starting to get into areas I'm not familiar with. What do you guys and gals suggest? I'm very handy and want to take care of everything myself...this is just getting a bit stressful with other life demands at the moment.

You want to know how to prove exactly what the problem is - do an overnight chlorine loss test (OCLT).

Bump your FC up to 5ppm with bleach when the sun goes down and before you go to bed. Make sure you test it after you do the bleach additions and make sure everything is off (no SWG, no pump, no ozone). Then, before the sun comes up in the AM, measure your FC again. I am willing to bet a box of Dunkin Donuts that your FC loss overnight is A LOT more than 1ppm....

 

[Redshift]

Re: Guts of QuadDE Filter

Brian,

30 to 50 people is not heavy use, that is more like a Public Pool...

Check out this chart... [FC/CYA][/FC/CYA] With a CYA of 100 your very absolute minimum FC needs to be about 6 or 7... Our chart does not even go that high for SWCG pools.

This is why your filter is clogging so quickly.

What are you using to test you pool water??

If nothing else, I would use liquid chlorine/bleach to increase your FC before and after you turn your pool into a public playground. (I'm just jealous.. I don't think I know 50 people, total... )

Thanks,

Jim R.

Geez, I didn't know that. I guess I only have a basic handle on the main chemical elements and how they interplay, but did not know about the relationship of CYA to FC. Learn something every day.

I use a test kit I have at home (Taylor DPD) for my testing.

You want to know how to prove exactly what the problem is - do an overnight chlorine loss test (OCLT).

Bump your FC up to 5ppm with bleach when the sun goes down and before you go to bed. Make sure you test it after you do the bleach additions and make sure everything is off (no SWG, no pump, no ozone). Then, before the sun comes up in the AM, measure your FC again. I am willing to bet a box of Dunkin Donuts that your FC loss overnight is A LOT more than 1ppm....

Ok, but the sun comes up SUPER early here. LOL. What about if the sun is already up but my pool is in full shade? Ok or no go?

I found the calculator. I do have granulated chlorine but I know it won't likely dissolve fast enough to do this test so I'll use liquid.

- - - Updated - - -

Also in the mean time, what should I be doing with my spare set of cartridges to prepare them for when I am ready to swap them out after water issues are solved?

- - - Updated - - -

Jim, also, forgot to answer your Intelliflo question. I run it at max speed, solar valve closed, return only, right after cleaning the filter cartridges to set my "clean" setting - usually comes in at 20psi on the gauge. So 3450 RPM is the answer.

 

[Jimrahbe]

OOH!!!

I love Apple and Spice Dunkin Donuts!!!!

Jim R.

 

[xyz]

I opened up my Quad DE filter after 9 months and was surprised how clean it was. So clean I likely won't clean it except every year.

I really like my Quad DE. between it and TFP my water is remarkably, even eerily crystal clear. At night, my girlfriend sometimes jokes by asking me why I emptied the pool again.

I do a few things to help.

1) TFP. I always keep my FC above the minimum; and if I ever screw up, I just do a Safety slam. I bring it up to SLAM levels, leave it there for 2 days, then do the 3 completion criteria. I'll even add a dose of chlorine if I let it get close to the minimum.

2) I run the robot every day. I think this acts as a mini filter so a lot of the stuff never gets a chance to get into the filter.

3) I use the hair net trick on my skimmer basket.


I also don't run my pump very fast {1200-1300} but run it for 8 hours [so my SWG has plenty of time to generate enough FC.


So....


I'd suggest you consider changing your perspective on FC. You may be breeding and killing lots of Algae. DE filters are really good at filtering out the algae, so you may just have an algae farm, and the Quad is constantly harvesting your crop. If it helps, I target my FC at 7, and get nervous at 4, I do a mini-SLAM if it gets below 3. And that is with a CYA of 70. With yours at 100 [and I'd guess higher], I'd think you would want to be around 10, and get nervous around 6.

Have you done the 2:1 dilution test to make sure your CYA is not well over 100? Or better yet, can you drain and replace 20-30% of your water?

Also, I use a middle of the road pump setting to check for a 25% increase in pressure. You may be overdriving something else in the system at 3450 and getting a false positive on your filter. Maybe check for filter pressure increase at 2000 or 1800.

Finally, given the chronically low FC, I'd suggest a safety SLAM for a few days.

- - - Updated - - -

Oh, and granulated chlorine is different than liquid chlorine. This may be the reason your CYA is so high. Switch to Liquid Chlorine for your SLAMs and any time you want an extra kick of FC. Liquid is the only way you are going to get ONLY an increase in FC, and not add other stuff.

 

[Redshift]

Jim, I missed the joke! Do share...

Jon, thank you for the info. I will search what SLAM is and yes I can drain and refill if necessary. I have a party on July 4 so I will want it looking good for that but given all the issues maybe after that I will go to town on it and start fresh. I think doing a drain and refill now is too risky to the party success but maybe there's time. I want the water to be nice and warm for my guests and we do heat with solar.

My water has been eerily clear for years now, even with keeping FC at 2.0-3.0 and ozone. But I dont' mind keeping it higher - besides FC, TA, pH, CYA what other things should I be regularly looking for to avoid this problem in the future?

Is there a suggested way to clean the filter with acid somewhere on this site?

 

[Jimrahbe]

Jim, I missed the joke! Do share...

Sorry... Matt said.. "I am willing to bet a box of Dunkin Donuts that your FC loss overnight is A LOT more than 1ppm.... " and I replied that I like a specific kind of Dunkin donut...

I agree 100% with Matt... you need to run the OCLT... Overnight Chlorine Loss Test

I also agree that I would test my filter at 2,500 or maybe 3,000 rather than at max speed..

Thanks,

Jim R.

 

[Redshift]

Sorry... Matt said.. "I am willing to bet a box of Dunkin Donuts that your FC loss overnight is A LOT more than 1ppm.... " and I replied that I like a specific kind of Dunkin donut...

I agree 100% with Matt... you need to run the OCLT... Overnight Chlorine Loss Test

I also agree that I would test my filter at 2,500 or maybe 3,000 rather than at max speed..

Thanks,

Jim R.

Duh, I see now.

So for OCLT should I be raising the level to 5.0 at sundown to do the test? And in the morning, does any sun up matter or only direct sun on the pool itself? I don't get any sun on the pool til later in the day. It's mostly shaded.

 

[JoyfulNoise]

Duh, I see now.

So for OCLT should I be raising the level to 5.0 at sundown to do the test? And in the morning, does any sun up matter or only direct sun on the pool itself? I don't get any sun on the pool til later in the day. It's mostly shaded.

Raise FC 5ppm or a little higher with bleach. Measure your FC addition about 30-45mins later to ensure you hit the target. Then let it circulate for another 30mins or so and shutdown everything. Also, no SWG on at all; turn it off.

Best to measure at sunrise before any light is hitting the pool....I know, you have to wake up early but it's just this once. Then measure your FC immediately.

Some tips - use a 25mL water sample and two scoops of powder so that the titration drop sensitivity is 0.2ppm/drop. Yes, it uses more reagent BUT it's more accurate. Also, try to get your water sample from the same spot in the pool and shove your arm all the way down into the water to collect a sample, don't use surface water.

Report back on the overnight loss.

 

[xyz]

What is nagging at my brain is your statesmen "...raise up to 5" instead of "raise up to 8. With this high a CYA, if you are keeping it well below 5, you may be at a perfect level to grow and harvest Algae. You may want to keep it at a steady higher level for a while and see if that helps with the filter.

 

[JoyfulNoise]

What is nagging at my brain is your statesmen "...raise up to 5" instead of "raise up to 8. With this high a CYA, if you are keeping it well below 5, you may be at a perfect level to grow and harvest Algae. You may want to keep it at a steady higher level for a while and see if that helps with the filter.

To do an OCLT, CYA level really doesn't matter. If algae is present and reproducing its normal rate, the OCLT will reveal that regardless of CYA level as the depletion of FC via sanitation reactions is quite fast.

 

[Redshift]

Raise FC 5ppm or a little higher with bleach. Measure your FC addition about 30-45mins later to ensure you hit the target. Then let it circulate for another 30mins or so and shutdown everything. Also, no SWG on at all; turn it off.

Best to measure at sunrise before any light is hitting the pool....I know, you have to wake up early but it's just this once. Then measure your FC immediately.

Some tips - use a 25mL water sample and two scoops of powder so that the titration drop sensitivity is 0.2ppm/drop. Yes, it uses more reagent BUT it's more accurate. Also, try to get your water sample from the same spot in the pool and shove your arm all the way down into the water to collect a sample, don't use surface water.

Report back on the overnight loss.

Went to the store - bought lots of bleach. Container says "yields 7.86% chlorine" which I assume is what to plug into the calculator?

What do you mean by "two scoops of powder"? My FC test is using the small sample tube with 5 drops each of R-0001 and R-0002.

Went out to check Cl then add bleach but found that FC was already at 5.0 so I guess I'll just wake up at 550am and check again.

 

[JoyfulNoise]

You don't have the right test kit for this. You need the DPD-FAS titration test kit - either the Taylor K-2006 or the TFTestKits TF-100.

As for the bleach, no you don't enter the % available chlorine. You use the weight % on the bottle, 8.25%. PoolMath does the rest.

 

[Redshift]

You don't have the right test kit for this. You need the DPD-FAS titration test kit - either the Taylor K-2006 or the TFTestKits TF-100.

As for the bleach, no you don't enter the % available chlorine. You use the weight % on the bottle, 8.25%. PoolMath does the rest.

Grr, okay. Which of the two kits would you suggest? I'll pick one up I guess.

While I wait for the kit, any advice for acid cleaning my filter cartridges and shocking the pool? Should I use the SLAM? Will I have enough time before the July 4 party?