Cat urine clear and no scent?

I would go to a different vet. Kidney failure is common in older cats and you need to have a vet take a urine sample from your cat and yze it. You cat could be drinking lots of water which is diluted her urine but there is some reason for her drinking so much water, diabetes or renal failure maybe. Also since your cat has FIV, it is very important that you catch things early on because of her compromised immune system. PLEASE SEE A VET!