Quote Originally Posted by dsmith3512 View Post
I've also had cheato fade away, but I run GFO in a reactor wouldn't that add iron?
You have an interesting point. I believe the issue is that the iron in GFO is insoluble (at normal pH) and just settles somewhere else in the tank or is removed by your skimmer. The iron additive @slapshot referring to is actually iron chelate which is a soluble complex of iron, sodium and a chelating agent which makes the iron soluble in water (i.e., available for plants to use).

Perhaps one of our resident chemists or biologists can weigh in with more info on this topic.