Pump /system gains system pressure but loses flow over time. Corrects with backwash. Keeps happening

Geoff-Y

New member
May 15, 2019
4
07920
Hi everyone,
So my situation is I have an in ground pool, DE filter, and everything seems to be operating normally and properly... for a while.

This pool was just opened for the season, on day 3 or so, this started happening yesterday.

What ive noticed is that the system runs fine for around 30 minutes-1hr, and the pressure will start to climb. Once it gets to around 40psi the pump is still running but there is no longer water moving through the jets, and there is visible air in the system at the basket.

A quick backwash (or long backwash) seems to correct the issue for another 30m to 1 hr, brings pressure back to normal.

What ive tried:
- backwashing (on backwash #5 in 3 days)
- Closing skimmers
-Ensuring water level is more than high enough
- checking seals on pump basket and auto chlorinator.

Any ideas?

TIA
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,633
Bedford, TX
Geoff,

I love the easy ones... :mrgreen:

What you describe is almost always because you have algae, whether you can see if or not.. I suspect you have been using 3" tabs to chlorinate your pool and your CYA is now way above 100 making your chlorine ineffective...

The filter is just doing what it gets paid to do.. Capture all the junk in the water... What you have is a chemical problem, not a filter problem. Filters cannot capture algae faster than the algae can reproduce..

I suggest the you read our pool school and see what we are all about..

To fix the problem you will need to do what we call a SLAM SLAM Process

But the first thing you need to do is test the pool water so that you know where your are...

To perform a SLAM, you will need an accurate test kit that can test FC (chlorine levels up to 50 ppm)... I use the TF-100, but the Taylor K-2006C will work as well also.. And yes, the "C" is very important...

Thanks,

Jim R.
 

Geoff-Y

New member
May 15, 2019
4
07920
Thanks for the reply fellas!
Plot thickens, and I think i was wrong re: backwash...
Backwash wasn't making it work, the act of stopping/ restarting the pump was making it work in any capacity.

Seeing a lot of bubbles in the basket by the pump, wondering if maybe im just pulling in too much air at the seal? Causing the pressure to go nuts?

Pressure resets and slowly climbs.
 

Geoff-Y

New member
May 15, 2019
4
07920
just to be sure i checked cya, in what my strips consider "ideal" 30-50 ppm. In fact all measures are coming up ideal, (roughly), so hopefully we can at least eliminate that!

Appreciate the replies again, heres what im looking at (sitting at about 36psi after 25 mins)

My water looks roughly how it normally looks shortly after opening. Slightly cloudy, with gradual improvement the longer i have the filter capably running. Shallow end can see clearly, deep end you can just make out return. Normal coloration (not green)
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,633
Bedford, TX
Geoff,

Simply put your multiport valve in recirculate and see what happens.. My guess is the pump will run fine and you will have good flow because you are not trying to push water through clogged filter.. Try that and report back..

Thanks,

Jim R.
 
Last edited:

Geoff-Y

New member
May 15, 2019
4
07920
Gang, I think you were right, and it was an easy one (thanks to you). So far so good but post cleaning and a new full batch of DE we are holding steady ~25 psi at 30mins.
Bubbles in pump basket were definitely throwing me off, (and are now gone) is that somehow related to the filter being dirty/low DE for my edification?

Thanks again,
 

Jimrahbe

Mod Squad
TFP Expert
LifeTime Supporter
Jul 7, 2014
14,633
Bedford, TX
Bubbles in pump basket were definitely throwing me off, (and are now gone) is that somehow related to the filter being dirty/low DE for my edification?
Geoff,

Most of the time, when you have bubbles in the pump basket, it is a suction side air leak, but when you have a clogged filter the water has no place to go and this can also cause the bubbles to form..

Keep in mind that cleaning the filter will only help for a while, as the algae in the pool water will quickly grow and clog the filter again, unless you kill it all first..

Thanks,

Jim R.