Since you all have been so helpful in the past with answering questions, I have one more 
Are there any test kits or anything out there you can use to see if your carbon is still active? My water stays "non yellow" mainly because I run ozone and have a lightly stocked tank, it is still only a few months old. But, I also run carbon to pick up any toxicants etc. I don't really want to throw away carbon away and replace it if it is still active though.
Any thoughts?
-Jeff

Are there any test kits or anything out there you can use to see if your carbon is still active? My water stays "non yellow" mainly because I run ozone and have a lightly stocked tank, it is still only a few months old. But, I also run carbon to pick up any toxicants etc. I don't really want to throw away carbon away and replace it if it is still active though.
Any thoughts?
-Jeff