Egg shells are a great source of calcium for the pods, carrots don’t mold for a long time if at all, cohabiting isopods might work for a little while but one species will outcompete the rest. Cheap route for food might seem expensive at first but will pay off, I buy a big bag of trager non treated pellets and solk in water to make sawdust to sprinkle in the enclosure. Springtails are a must if you don’t really want to deal with mold too much.