when i shut change my carbon cartridge??

[rppr21]

:confused:i got a merling ro. like 2 y and i do 100g wc every week. im worry that some how i found out that is time to change my carbon cartridge too late. i make test once in a wile and still look like is working fine. is a determinate time to change that thing??? my ro got 2 membrane and 2 carbon thing.

[Roxanne]

...errrr...do you mean you have an RO Unit and you want to know how often to change the carbon?

Roxanne