Rust inside of pool filter

[GoldMember]

Hello all. Last month when I went to clean my pentair filter cartridges, I noticed some significant rust on the hoop that I think helps keep the shape of the filter housing. The filter is 5 years old. I assume this is stainless steel, right? Why/how would it be rusting? Is this a problem, or is this normal? Thanks everyone.

 

[Mdragger88]

I believe this is a common issue.

Pentair filter rust

Hi everyone, Like others, our Pentair filter has a fair amount of rust coming off the inner steel ring. I started to notice it a year or so ago and it does seem to have gotten worse. I've checked out a number of posts and it seems this is somewhat common occurrence with Pentair filters. Our...

www.troublefreepool.com

 

[HermanTX]

Hello all. Last month when I went to clean my pentair filter cartridges, I noticed some significant rust on the hoop that I think helps keep the shape of the filter housing. The filter is 5 years old. I assume this is stainless steel, right? Why/how would it be rusting? Is this a problem, or is this normal? Thanks everyone.

It is pretty common. That band is not all stainless steel as you can see where the weld is will rust.
One day you may need to change out the band.

 

[pjt]

Is this a problem, or is this normal?

It's very common. It shouldn't happen, but it does.

 

[JoyfulNoise]

It’s caused by the spot welds on the band. The manufacturer of that band, probably not Pentair, doesn’t use the proper post treatment processes to clean up the weld points. The welding process damages the stainless steel and causes it to recrystallize into a form of iron that is no longer corrosion resistant. There are ways to heat treat the metal as after welding to improve corrosion resistance but I’m pretty sure the maker skips those processes to save a few pennies per part.

FWIW, my filter is going on 12 years old, has the same band, similar rust issues, and works just as well as the day it was installed.

If you want to clean up the rust, use some Bar Keepers Friend liquid cleanser on a Magic Eraser sponge and it will remove the rust and restore the luster of the band.

I would also suggest redirecting the input water diffuser so it’s not totally pointed at the band. Maybe rotate it a few degrees either way.

 

[GoldMember]

@JoyfulNoise Great advice. Thank you, and everyone else who took the time to respond. Much appreciated!