You need to wait till the tank is completely drained, then rinse. At first there wont be any water coming out, but even as the water does start to drain out, the water pressure from the hose gives it enough force to push back up into the tank. As water flows in, it stirs things around and exits at the same time, helping to rinse the tank walls and floor. As long as you follow best black tank practices, mainly being very generous with water, the Rhino Blaster should be able to keep your tanks clean.
I use Bio-Pak drop-ins to help keep it fresh: https://amzn.to/4koQh3o