leaving old carbon in canister

["Adam Cantrell" <blizang at ameritech_net>]

Hi list, it seems as if using activated carbon is controversial in the
realms of planted aquaria, so I'm considering ditching it in my 55gal. DIY
CO2, medium plant-load, light fish-load tank. My question is, can I just
leave the current batch in my cansiter and use it merely as a home for
biological filtration. In other words, does the carbon really ever expire
fully to the point that it won't be filtering any of the beneficial trace
elements from my water? The carbon I have in there is about 1.5 months old.

If not, what do you recomend I put in the canister filter to take its place?
I have the 'Magnum 350' with the blue filter material wrapped around the
container that holds the carbon. Should I just wad up more of that blue
filter material and put it in the carbon cantainer?

Adam.