This is my cactus. It's a year old and recently has started getting white spots all over it?? It's getting fertilizer (not sure if it's cactus specific) and lots of sunlight on my window. Watered once a week. It's also wobbly because it has shallow roots but otherwise it was growing very very well since I got it as a small bud but then these white spots were showing up and I'm concerned. Any ideas?? Soil is cactus specific too!!!! Whiteness starting on the top, bottom is green and healthy. Indoor plant no exposure to outdoors.