Some Carbon use/light intensity observations for ya.

[rossb]

Jon if I added an inline filter to one of my returns, do you think that would work? I have 2 1-1/2" abs returns from my tank. I could make an inline 4" filter that could be changed out quite easily. This would force about 1/2 of the water to be filtered. I could also have an overflow incase it backed up. Can you buy charcoal locally (just to test the concept)?

I also have a diatom filter I could adapt. I think I might have to try this.