I use it only every two months. I let it sit in there for a few days too and then I take it out. I use activated carbon for reducing some toxins of the corals and other bad ingredients.
To make only the water clear, I often use Easy Life - it's softer for the corals than activated carbon, which often reduces trace elements rapidly.
Especially Xenidae have sometimes problems with the usage of activated carbon.
But if you do regular water changes (20-30 % at month), it wouldn't be a problem.
Greetings
Sudad