DI resin question

[fishman]

For those of you that buy the reusable cartidges and refill the resin, do you replease all of the resin or just the part that is exhausted? It looks like to me when I go to replace the resin, the worst is at the top and bottom of the catridge.
Thanks

[seaham358]

Toss it all, the water raises up through the filter so the bottom gets first shot at picking up the waste. Just to save a few pennies its not worth using the upper section. It all contains something that is why a TDS meter picks up a reading. So the top is not 100% either even thought it looks fine.

[fishman]

Thanks Seaham!