I am confused over the role of activated carbon in filtration of planted tanks. In the past I had used them while first starting (and failing!). At one point someone at APS said that one should never use activated carbon in a planted tank as it removes the ferts, or weakens them. While reading over a lot posts here, I see recommendations for using them.

What is the "official" recommendation on using activated carbon?

I only have several small tanks, from 5.5g to 20g and use either h.o.b. filters or a small Filstar XP1 on the 20 gallon. At the moment I only use the activated carbon as part of the filter cartridges for the little Marineland Eclipse System 6 I have. I wish I had the tanks and space to experiment both ways at this time!