Gravel and KH Warning PLEASE READ!
So I did a bit of an experiment, and found out that my aquarium gravel WAS raising the KH! This is gravel that was bought at a pet store (I don't remember the exact brand). As a warning to all of you, test your gravel (by putting it in RO water) to see if it raises the KH/Gh. Just because it is ''aquarium'' gravel doesn't mean it will not affect your water chemistry.