RO Cartridge

[artur]

Hi everyone. For over 2 years Im using 90 gal. per Day SpectraPure RODI filter. I change around every 6 months my Sediment, Carbon and DI Cartridge. Im testing water with TDS meter, when it gets 0.01 I'm changing them. I have never change RO Resin. I read somewhere that 2 years is mark for replacement. What you guys do? Thanks.

 

[Linwood]

I find my DI resin needs changing more often than the other filters. I change the DI media when I start getting a non-zero reading on the TDS meter.

Changing the RO membrane would be when I start seeing more than 5% or so TDS reading compared to input water, out of the RO (but not DI) membrane. I've never changed mine (less than a year).

In theory the RO Membrane should be the least frequently changed item you have, DI media probably the most frequently changed, and sediment and carbon block in the middle, though where these fall depend a lot on the quality of your input water.