Recently we relocated a cactus into a new flowerpot. When it was planted the soil would evenly occupy the flowerpot and adjoin the flowerpot side walls. The soil isn't cactus soil, but just regular soil that we bought from a local shop.
Now the soil shrank, formed a stiff cylinder and that cylinder no longer adjoins the flowerpot side walls - there's about 10 millimeters of air on one side of the soil cylinder and the other side seems to have slanted onto the pot side wall.
The cactus looks just fine.
Is that a problem? How do I address it? Do I loosen the soil or should I just leave it untouched?