1+ year old RODI filters still look brand new? Swap out it let it ride?

[george9]

Hey everyone,
I am kind of dumbfounded why my RODI filters never seem to get dirty. Not that I am going to complain about it, but it is peculiar to me that these filters and DI resin which are each over 1 year old still look almost brand new. There is also a singular exhausted ring within the DI resin but 80% of it still appears to be good. What would cause only a ring within the center to exhaust like that? It’s very odd to me, when the water is turned off, the water line within the canisters is well above where this brown ring is.

My tap is about 150 TDS and it is still producing 0 TDS water and I have no weird algae issues going on so no real reason to swap the filters other than the age. The DI was last changed in Nov. 2022, and the pre filters were changed in January 2023.

My gut is telling me to just change them out because it is well overdue for DI and pre filters but they look brand new and I’m still getting 0TDS water so don’t want to throw money away. I make about 10-15 gal a week.

Looking at the current state of my 1+ year old filters, would you swap them out purely because of their age, or let it ride until they get more exhausted or I start getting 1TDS?


edit- mods, sorry for the typo in the title. It should read “swap out, or let it ride?”

 

[mues]

If you're still at 0 TDS, I don't see a reason to change them.

 

[george9]

If you're still at 0 TDS, I don't see a reason to change them.

that’s what I’m thinking too, but am a little thrown off by the (visual) longevity of these given the manufacturer and general sentiment here is to change pre-filters around every 6 months. I’m over double that time and still snow white, my tap isn’t even particularly good

 

[Johnd651]

One of the things I have heard in the past was to replace them to prevent mold growth. I think your right thought, 0 TDS, let it ride.

 

[mues]

that’s what I’m thinking too, but am a little thrown off by the (visual) longevity of these given the manufacturer and general sentiment here is to change pre-filters around every 6 months. I’m over double that time and still snow white, my tap isn’t even particularly good

10-15gals a week is relatively low usage... I think you'll be fine. TDS and tank will tell you if otherwise. As expensive as those filters get, I'd let it ride until it tells you otherwise

 

[disaster999]

If your DI resin still produces 0TDS water you could leave them be. I would change out the pre-filter and carbon filter tho. They are cheap anyways and prolong the life of your RO membrane.

 

[dschuffert]

Based on 0 TDS output, I think you are fine. I let my DI resin run until the TDS goes above 0. I change the sediment and charcoal filters when I see the usual psi decreasing. I change the RO membranes at 1.5 to 2 years.

 

[Ironwill723]

They tell you to change them so you'll buy more often from them. 0 TDS you are fine. They look brand new still.

 

[KStatefan]

I change mine based on the following

Sediment: pressure drop across filter
Carbon: gallons used vs capacity
Membrane: Rejection < 97%
DI: Color change and/or TDS reading

 

[george9]

I guess Miami tap water doesn’t have much sediments in it that the pre filters appear to be untouched?

Any ideas what would cause the DI to exhaust in a strange ring like it has?