My buddy has an extra Calcium reactor set-up laying around, and I am going to give it a shot. Not sure how many out there are actually using one. I know it's a dual stage reactor, and i'm wondering what types of media people are using (ie: ARM, Gen-X, BA CoraLazarus, etc.) I have seen some people using 2 diferent brands in each reactor, and some just using different grain size of ARM. I am wondering if using 2 different products would be possible due to different pH ranges to dissolve the media. Any help is appreciated.