High pressure at DE filter

[WDVinAZ]

HI, I have a perplexing issue with my DE60 Filter. The pressure starts at 16 lbs and my pool vacuum runs fine. The pressure rises to over 35-40 lbs over the course of an hour and the pool vac stops moving. The suction at the vacuum inlet is at Max as measured with my spring pressure device when at 16 lbs but below Min when the pressure rises above 35 lbs. I can get the pressure back to 16 lbs by backwashing for a short time but then it rises to 40 lbs over an hour. I have just replaced the grids in the filter with a new set. Any suggestions?

 

[ajw22]

You have an algae problem clogging your filter. even if your pool water looks clear.

How many gallons in your play pool?

What test kit do you have? You need the TF-100 Test Kits or the Taylor K-2006C. Get the XL Option as you may go through a lot of tests in clearing the algae.

Then you need to follow the SLAM Process to clear the algae.

Get the test kit and post your water chemistry.

Swimming Pool Algae: Basics and Prevention

The best offense is a good defense: prevent algae in your pool with chlorine, and avoid expensive algaecides and shock! No more green pools!

www.troublefreepool.com

 

[WDVinAZ]

Thanks for your reply. My pool is pebbletec 14-16000 gallons. I use a Taylor K-1004 Pool Test Kit.

 

[ajw22]

Taylor K-1004 test kit will not let you test FC accurately and over 5 ppm or test CYA. Both are necessary for proper pool chemistry.

I suggest you read ABCs of Pool Water Chemistry and Pool Test Kits - Further Reading

Put your pool gallons in your signature.

 

[Jimrahbe]

WD,

The number one reason for the symptoms you have described is that the DE filter is good at its job. It is filling up with something and most likely algae.

Thanks,

Jim R.

 

[WDVinAZ]

I had my water tested at Leslies, the results are below.
I just shocked the pool 2 days ago before changing the filter grids with 2 bags of Leslies pool shock.
I last changed water in May, 2013.
My last measurements before shock treatment were pH 7.2, TA 120 at pool Temp of 72 degF (K-1004).
I have maintained this pool since new for 18 years. For the most part maintaining pH and TA along with visual clarity has served me well.
Except for adding acid or ash once in a while I have used only 3 " CL Tabs from Leslies.

Leslies Data:

FC 11.74
TC 12.33
pH 7.2
TA 61
CA Hardness 481
CyA 132
Iron 0
Copper 0.1
Phosphates 181
TDS 2000

Maybe it is time for a water change before doing a lot of chemical balancing.
I agree that something is clogging the filter but I'm not convinced it is algae.

 

[duraleigh]

I agree that something is clogging the filter but I'm not convinced it is algae.

What do you think it might be?

 

[ajw22]

- 3 " CL Tabs from Leslie
- CYA 132 although likely higher since Leslie testing does not go higher
- Leslie’s testing
- clogging filter

We see this problem over and over. Same disease, same cure. It is just water chemistry and science which folks at Pool Stores usually don’t understand.

ABCs of Pool Water Chemistry

 

[WDVinAZ]

duraleigh - Something in the line that is drawn in but does not backwash out then retreats at backwash.
I have taken out the motor to the pump and found some plastic debris in the impeller and the diffuser was cracked.
I removed the debris and swapped the cracked diffuser with the one from the SPA Motor/Pump.
I also have some water leakage at the Return/Backwash handle and some air leakage into the pump strainer cavity.

ajw22 - I have read the ABC's and I'll read again. I also see where liquid CL seems to be preferred in this forum as opposed to Leslies CL tabs.
Do you still think it is an algae issue?

I'm going to try a few things that may prove to me it is algae.
(1) I have a second grid assemble. I'll remove the grids from one of them and run the filter with no grids to see if the pressure remains constant.
(2) I'll change the water. I usually change it at 5 years, it has been 7 now so I figure that should be done anyway.

Thanks for your assistance. Should I be looking for a major equipment replacement about now? This install has been baking in the AZ desert sun for 18 years.

 

[ajw22]

I also see where liquid CL seems to be preferred in this forum as opposed to Leslies CL tabs.

You do not understand the problems that a high CYA of 132 causes. Using CL tabes just keeps on icebreaking your CYA. The higher your CYA is then the higher you need to have your chlorine level to be effective. With too high a CYA you can't get your CL level high enough and then you have algae probelms.

CYA - Further Reading

www.troublefreepool.com

We use the FC/CYA Levels to determine what CYA level and FC level will work.

Do you still think it is an algae issue?

Yes. It is science. Do you believe in science and chemistry?

I'm going to try a few things that may prove to me it is algae.
(1) I have a second grid assemble. I'll remove the grids from one of them and run the filter with no grids to see if the pressure remains constant.

Your MPV valve should have a RECIRCULATE setting. Just put it on RECIRCULATE to bypass the filter.

(2) I'll change the water. I usually change it at 5 years, it has been 7 now so I figure that should be done anyway.

Every time you do that you reset your high CYA problem. If water is cheap then do it. The only way to lower CYA is by draininga nd replacing with gresh water. But understand what is really happening. Your water is not "stale". It has a high accumulation of CYA from the tablets you have been using.

Thanks for your assistance. Should I be looking for a major equipment replacement about now? This install has been baking in the AZ desert sun for 18 years.

I don't see why you should spend money to replace perfectly good equipment if it is functioning properly.

What problem are you trying to solve or new features you want?

 

[Rancho Cost-a-Lotta]

Leslies Data:

I think this is the root of your problem. If you can rule out a water chemistry issue, you can move on to mechanical issues. The problem is these test results can't be trusted. You've got three experts with 25 years+ experience at TFP all saying the same thing...water chemistry issue. I rode the pool store roller coaster for 10+ years, spending thousands, before I invested in a $70 test kit. Since, I've save hundreds and have enjoyed a crystal clear pool. Order up a TF-100 or Taylor k-2006C.

Best wishes!

 

[WDVinAZ]

Good, thanks for the lesson.
I don't have recirc option or I don't know how to do it with my MPV valve. I would like to do this if I can, much easier.
There may be another way to bypass but pipe labels are sunburnt off.


Yes, I believe in Science/Chem along with KISS principle.
So if I change the water I start over needing less CL.
My water cost $4.62/1000g so about $75.
As far as new equipment, I only want my status-quo back. I don't fix what ain't broke and I fix what I can myself before calling in the pros as in $$'s.

 

[proavia]

You don't have a multiport valve, you have a push/pull backwash valve. It doesn't have a recirculate option.

If you want to take control of your pool and save money in the process, order a TF-100 and a Speedstir from TFTestkits. Test results from pool stores can't be trusted. Also, get the PoolMath app and learn to use it. Source liquid chlorine locally - Lowe's, HD, Ace, Walmart and a few local pool stores carry it. Read up in PoolSchool and adhere to the FC/CYA Levels.

If your water is 7 years old, the CH level is probably much higher than what the pool store results indicate. CH can only be reduced with water exchange - drain/refill and splashout. CH continues to increase with water evaporation. And your fill water - if not using a water softener to furnish refill water - is between 200-250. Since we live in the desert and pretty much the entire pool volume evaporates every year (or more often), your CH increases at least 200 per year.

If all you have been using is 3" tabs, chances are your CYA is much higher than listed also.

If the filter pressure increases rapidly - you have an algae issue. Chances are you equipment is fine.

Best bet may be a drain/refill. Just be aware of our increasing temperatures (90+ for the next week or so) and if you do drain, use a hose to keep the pool surface damp. Uses as many hoses as possible to refill. Your other option is to wait for cooler weather - but it may be a while.....

 

[Flying Tivo]

As far as new equipment, I only want my status-quo back

Your best upgrade in equipment right now besides the test kit would be a MPV for your filter( example), it would give you more flexibility.

 

[wireform]

Or install a jandy bypass valve before the filter for this purpose only.

 

[WDVinAZ]

My water is clear which is what I started out to do so that is an accomplishment but I did that by constant backwashing.
Due to the backwashing, the water level is already down a few inches which will help with a water change as next step.
So, drain/refill. proavia, what is splashout?
I'll be back with results of that effort. Thanks for the guidance.

 

[proavia]

Splashout - water exiting the pool thru swimmers having fun... Kids and adults splashing water out of the pool.

Good luck with your drain/refill. With our temps going from 90 to over 100 in the next week, do use care in keeping the entire interior pool surface damp throughout the process. How much of the pool is in the shade?

Have you ordered a test kit yet? Adding a Speedstir will put you into free shipping territory with TFTestkits. The only other test kit we recommend is the Taylor K-2006C. Pool store testing and advice really isn't sustainable. And it's darn near impossible to mix our advice with that of the pool store.

 

[WDVinAZ]

Drain/Fill is complete.
Drain 26 hrs (1/3 hp Drummond submersible pump from Harbor Freight)
Fill - 12 hrs (4 bibs from house)
First tests show CL 0, PH 8.2, TA 160. ( as per K-1004)
It will be later today before I can start the filter after I clean it out.

I have not ordered the TFT100 yet, I added CL tabs for now until I get a new test/maint process in place.
I also recalculated the pool + SPA volume = 14,212 Gal.

 

[Flying Tivo]

Tablets add chlorine very slowly. Add liquid chlorine to bring up to 5 ppm and lower ph to 7.6

 

[wireform]

Drain/Fill is complete.
Drain 26 hrs (1/3 hp Drummond submersible pump from Harbor Freight)
Fill - 12 hrs (4 bibs from house)
First tests show CL 0, PH 8.2, TA 160. ( as per K-1004)
It will be later today before I can start the filter after I clean it out.

I have not ordered the TFT100 yet, I added CL tabs for now until I get a new test/maint process in place.
I also recalculated the pool + SPA volume = 14,212 Gal.

I would not be puting in tablets at this point as you don't know the true CYA yet. Go get some liquid chlorine and add per pool math to keep the alage at bay. Order that kit or you can have a swamp before you know it.