Tropicals & Tender Perennials: HELP!!! My black thumbs are killing my aroids, 1 by Marissa7

Marissa7 wrote:
I recently purchased 3 plants - A. macrorrhiza, C. antiquorum 'Illustris' and C. escuelenta 'Black Magic'. They arrived very healthy looking....
I repotted them in large pots, using potting mix from our local nursery (called 'Bumper Crop') and added some compost that I'd purchased as well. I live in Livermore CA..and do NOT know what zone I'm in. They are currently under my patio cover and receive bright morning (southern) sunlight, but they are not directly in the sun. I was told that they like to be kept in moist soil, so I have been watering them every other day. I also used Miracle Grow on them shortly after repotting them. I don't know what I'm doing wrong, but they are not happy. And I adore these types of plants...I'd love to "get hooked" but not if I'm just gonna kill each one that I purchase....please HELP ME!!

Here is a pic of the Illustris...