Anyone ever have a filter that won’t backwash?

[Turkish]

No good deed goes unpunished. You folks have been a lifesaver, so here’s one more.

I recently returned my pool to service after a pump outage. The pool was quite dirty and pump discharge pressures are understandably high. When I try to backwash, I get what appears to be acceptable flow through the waste line, but it never turns dirty. It doesn’t appear that any material is actually being removed from the filter. Returning the filter to service, discharge pressures are unchanged.

Any ideas what’s wrong?

Filter is a Tagelus and valve is a Pentair TM-22. Tia

 

[Texas Splash]

Some thoughts since your pool was quite dirty when you started it back up:
1 - Check plumbing for potential clogs. You may have unknowingly sucked-up something.
2 - Open the filter and do a deep cleaning of the sand if you haven't done so in a while.
3 - As a comparison, you might also consider running the filter on recirculation to compare water pressure at the jets.

 

[Turkish]

Re: #1. What area of the plumbing could have a clog that would present itself this way?

Discharge pressure on recirc is 1-2 psi lower than while filtering. This seems lower than I’d expect, but I’ve never paid attention to recirc pressure. I just know discharge pressure is a little high. And, oddest of all, backwashing doesn’t seem to be discolored at all.

 

[Texas Splash]

I was concerned that perhaps you developed a partial suction line clog based on the condition of the pool and subsequent cleaning/vacuuming. Perhaps that might be effecting the water circulation and pressures. Still odd your backwash doesn't appear to show any changes.

- Can you post a pic tomorrow of your filter and equipment pad?
- Have you ever performed a deep clean of the sand?
- How old is the filter and sand in it?

 

[Turkish]

I was concerned that perhaps you developed a partial suction line clog based on the condition of the pool and subsequent cleaning/vacuuming. Perhaps that might be effecting the water circulation and pressures. Still odd your backwash doesn't appear to show any changes.

- Can you post a pic tomorrow of your filter and equipment pad?
- Have you ever performed a deep clean of the sand?
- How old is the filter and sand in it?

I have not done a deep clean. Trying to research filter cleaning now. The sand is probably 3 years old but had been giving me no trouble.

 

[Texas Splash]

Below is the link for a deep cleaning. Unless your plumbing configuration was moved/changed, I couldn't help but wonder about some sort of circulation issue based on your description. But perhaps the filter itself is overwhelmed with junk and a deep clean might do the trick.

Deep Cleaning a Sand Filter

This post will walk you through the anatomy of a sand filter, and then provide a video at the end for how to deep clean your sand filter. The filter used in the photos and videos is a Hayward S180T top mount sand filter. The images are of a similar filter. Obviously not all filters are...

www.troublefreepool.com

 

[Turkish]

Honestly, in 6 years of having this pool, it hasn’t looked this bad. Pump was out of service for 10 days, FC had gotten low, out of town for holidays, yada yada. As such, I’m not sure how long it should take to clear up. I’m starting to wonder if it’s filtering anything out at all, as in wondering if something has gone wrong in the multiport.

 

[Texas Splash]

I’m starting to wonder if it’s filtering anything out at all, as in wondering if something has gone wrong in the multiport.

Let's stay focused on some basic items, then process of elimination. Tomorrow let's try to start fresh with the following:
1 - Pics of your filter and entire pad set-up
2 - Full set of water test results
3 - A pic or two of the pool's water
4 - Take a moment to update your signature with all of your pool and equipment info. See my signature as an example. It can help us later.

We'll do our best to get you through this.

 

[wireform]

Perhaps you've used non recommend potions such as floc or the like that will destroy the sand and turn it into a gummy substance so not it's not filtering but channeling through the sand so now when you backwash it's essentially doing nothing for the dirt.

 

[Turkish]

Perhaps you've used non recommend potions such as floc or the like that will destroy the sand and turn it into a gummy substance so not it's not filtering but channeling through the sand so now when you backwash it's essentially doing nothing for the dirt.

No additives used whatsoever, but I have wondered if something is causing channeling thru the sand bed.

 

[Texas Splash]

but I have wondered if something is causing channeling thru the sand bed.

If so, the sand deep cleaning should take of that issue.

 

[Turkish]

Let's stay focused on some basic items, then process of elimination. Tomorrow let's try to start fresh with the following:
1 - Pics of your filter and entire pad set-up
2 - Full set of water test results
3 - A pic or two of the pool's water
4 - Take a moment to update your signature with all of your pool and equipment info. See my signature as an example. It can help us later.

We'll do our best to get you through this.

FC-3ppm, pH-7.8, DPD reagent had spoiled so no other Cl results right now, CYA-50, TA-60, CH-250

Eta: you may notice a surprising lack of unions

 

[Texas Splash]

you may notice a surprising lack of unions

Rats! That will require a little more effort from you for the deep clean to get that MPV off the top. I don't think you have enough wiggle room with the pipes to do it otherwise.

 

[Texas Splash]

On a side note, your FC is a bit low and the water appears a bit cloudy. Since you are/were battling that algae recently, have you actually completed the SLAM Process, or are you waiting to receive more FAS-DPD reagents to increase, maintain, and test the elevated FC level? Or have you done an Overnight Chlorine Loss Test?

 

[Turkish]

Funny you should ask about the SLAM. I’m still dealing with a lingering pump issue after the motor rebuild. I am waiting on delivery of a new seal plate and am hesitant to run the pump overnight with it leaking.

I picked up some unions this morning but can’t decide if I want to tackle these plumbing mods today.

Eta: I tried a backwash again, despite pressure gauge having not really moved. I caught some of the backwash water in a white bucket. It is definitely dirtier than pool water, but not nearly the color that backwash water typically is. I’m thinking channeling in the filter. Filter is picking up a little bit of Crud, but not much. If so, the deep clean is what it needs.

 

[Bperry]

Have you considered that the filter just may not be that dirty compared with the pool water? Your chlorine is pretty low and so I might try the SLAM process once you have fresh reagents and see how it goes. The filter alone won’t clear up water like that.

 

[Turkish]

Have you considered that the filter just may not be that dirty compared with the pool water? Your chlorine is pretty low and so I might try the SLAM process once you have fresh reagents and see how it goes. The filter alone won’t clear up water like that.

I have considered that, and it’s a really good point. I’m mostly focusing on the cleanliness of every backwash I’ve done the last couple of days, compared to every other backwash I’ve done the last 6 years. That’s still a little anecdotal, though.

 

[wireform]

I'd recommend to deep clean the filter now and cross it off the list.

 

[Bperry]

I have considered that, and it’s a really good point. I’m mostly focusing on the cleanliness of every backwash I’ve done the last couple of days, compared to every other backwash I’ve done the last 6 years. That’s still a little anecdotal, though.

Yea, if your filter had unions on it I’d just suggest popping the top off and taking a look.

 

[jmastron]

Is it just those 3 pipes that are visible? The pipes themselves look pretty accessible; I'd consider just cutting them along the vertical runs and gluing in some PVC slip-slip unions from the hardware store. I assume the whole MPV (with part of the piping attached can then just unclamp and pull off?