Carbon in the marine tank...

[Sushiman]

I'm a 24/7 passive style in my sump. Change your water & life seems good /trace replaced. I change my carbon frequently & also passivly run Purigen & phosphate media alongside.

[kwirky]

i actively run 1 cup of carbon in my 120 gallon setup. I find it mostly helps with making sure the skimmer doesn't go crazy.

I change the carbon every 2 weeks.

[Ruth]

I run carbon passively in my sumps and change it out about every 3 to 4 weeks. I think that it helps with water clarity.