I run Carbon but it's in a reactor. Personally I don't think carbon (or any media) is being used to it's potential when run in bags. With very few exceptions, you end up getting a "tea bag" effect with the water running around the bag. The effect gets worse if you don't rinse off the detritus that can build up on the outside on a regular basis.
I think a lot of the "reasoning" behind people saying carbon is bad for coral is that it does remove trace elements... Keep up on your partial water changes though, and this isn't an issue. Another reason people say not to use it (and the reason I don't in FW) is because carbon really doesn't last long, in a lot of cases it would normally be exahusted in less than a week (depending on other factors of course).
YET another reason people say not to use it is most (if not all) carbons can leach phosphates. I get around this by running GFO as well in another reactor. I did reacently switch to Seachem's carbon spheres (sorry don't remember the name) but I haven't tested it to see if it does leach. Because the GFO works so well, I never see very high PO4 anyway so I'd never be able to tell from my tank.
So some things to consider there anyway
. May not work well in your app. but if you can run it, probably not a bad idea to.
Chris
