What do i replace first? Rodi

[Jake_the_reefer]

So my rodi system just started producing 2 tds water which is telling me I need to replace something. My di is a quarter depleted the ro I am assuming is fine. Should I replace the carbon or the sediment or both cartridges?

 

[reef lover]

Sediment

 

[homer1475]

A TDS meter on the incoming water to the unit, then before the RO, and after the Di will tell you which filters need to be replaced.

If it were me and I used to have that unit, I just replaced both cartridges at the same time as the color changing DI doesn't always change color all the way up to the top when depleted.

 

[Gareth elliott]

if can look inside your di, make sure the center hasnt changed faster than the rest.