Poor Luna.
I have been down the urinary porblems road 4 times before my vet suggested putting the entire clan on Hill's prescription diet C/D. (I had 1 cat who needed bladder stone surgery, one who needed a catheter inserted to open up the passageway and 2 caught early with crystals in the urine ). After their initial treatments they (and ALL) did very well on the special food. I would NEVER take them off the food because the expence of the UTI is WAY more than the extra expence of the food. (and improper "peeing" was the first sign in all cases)
The cats are also on bottled water because our water can be quite high in minerals and other "stuff". It may or may not be helping, but I don't wish to tempt fate. I may just try top find those cranberry treats also as an extra helper. (I still did have 2 cats come down with a simpe UTI (not the crystals) while on the food, so the treats couldn't hurt). What are they called again? And where did you get them, Sas?