This is likely a bladder problem, but potentionally also a kidney problem. Many reasons for blood in the urine; infection, metabolic disease, toxin, cancer, etc.
I know it is tempting to avoid the veterinarian for a cheap fix, however this is not a good case to try that. Diet changes will help if you have a cat that produces a crystal-saturated urine, antibiotics will help with a bacterial problem.
However if it turns out you have other reasons for this
presentation, then treatment will need to be tailored for the individual. Find out what the true underlying cause is and address that for a long-term resolution, don't depend on band-aid solutions to tough problems.
Dr. Van Lienden
Dr. Raymond Van Lienden DVM
The Animal Clinic of Clifton
12702 Chapel Road, Clifton
Virginia, U.S.A. 20124