carbon? who runs it

[Willow]

ive never really used carbon before unless i was having problems but ive recently decided to start using it regularly. i was wondering how much do you use and how often do you change it out.

i grabbed one of those big cans of black diamond from j&l and am running a cup of it in a micron bag in the last chamber of my sump. trying to figure out if i should use more and is a month to long to leave it, i suspect it stops working after a week or so.