Yeah I guess zero-g really fucks with the urinary system. Kidney stones are a big issue too. IIRC even after returning to earth, astronauts have a much higher incidence of stones for the rest of their life.
Idk if catheters would be a good option, since those increase the chance of a UTI - ideally things only ever move one direction through the urethra, since probing shit into gives pathogens an express trip to the bladder. My best guess is a strict diet and drink regiment made specifically to rule out kidney stones, and scheduled/frequent urinating so bacteria don’t have a chance to propagate.
Iirc they have a similar setting, where the spiders turn into derpy looking spheres.