Some Carbon use/light intensity observations for ya.

[Doug]

Jon, its a long story from a few years ago. Just wondered about another carbon, like Black Diamond.

By the way, I run carbon 24/7. Always have. I change it when I remember. Either run it passive in the sump, {if I have one}, or in a hang on power filter.

Currently I have two medium sized carbon bags, about 3/4 full in a power filter. Usually switch one about every 3rd week.

Without a skimmer, I require it to compensate for my turf scrubber.