if you are killing cissus amazonica, you are doing something terribly wrong. This plant is basically a weed for me, it grows incredibly fast! It does ok in high light and low light (leaves get smaller or bigger respectively). You are either swamping it in an oversaturated soil or you are drying it up. It needs good humidity and like all epiphytic cuttings, needs to be kept wet until it roots. I would recommend growing it in higher light and letting it find it's way around the viv after it roots and starts growing...