At this point the most important thing is to wait for the results of the tests. What kind of stone/sand it is determines the future plan of action. My boy has defected HUU-gene that causes hyperuricosuria and it can cause stones in the bladder as well as in the kidneys. This condition doesn't necessarily require medication. There is good chance it can be managed with proper nutrition. But if the stone is the kind that doesn't dissolve, operation is needed. But in a way that's better, you sort of "start from a clean table". The nutrition that dissolves stones is really quite poor and can cause other problems and some type of stones can not dissolve. Hang in there!
UTI confirmed. Its an infection, e coli and something else I can't pronounce. Salo is on antibiotics for 2 weeks and getting his urine tested again in 10 days to see if the meds are working. As for the stone, the plan is to leave it and do another ultra sound in the future to see if that situation improves.
They're not sure if the infection came from the crystals/sand in the bladder. Vet is giong to deal with that later, after the infection is resolved.