Q.fiscus tree
What do I do? We have a cat that likes to relieve himself in the plant box and we have cleaned the mess out, but it looks like the mold or mildew is coming back. First, do we have to replant the tree in new soil? If so, how is this done without bringing the problem to the next change of soil?

This website has some good suggestions: http://moldblogger.com/mold-removal-tips-for-houseplants-and-gardens/
And here is an article with tips on how to discourage cats from disrupting your garden: https://www.gardeningknowhow.com/plant-problems/pests/animals/cat-repellent.htm