Back patio (concrete) is stained with dog urine. Ive tried various cleaners,
turpintine, bleach and scrubbing. No luck. Don't want to paint the concrete
unless I absolutely have to.

Any hints appreciated.

-David

There are stains for concrete that would look a lot better than paint,
which would look funny. One site I googled for is
www.concrete-stains.com though obviously you could go to all the
trouble of using something like that and still have the dog pee stains
noticeable.

From their description maybe their product works like dog pee, it
interacts chemically with the concrete.