Easy and quick extra rinse for black water tank

I added a third twist-on valve to the waste outlet. With the grey tank nearly full, I open the third valve and the black tank valve. When the black tank is done draining, I close the third valve and open the grey valve to let it equalize into the black tank as a rinse. Next, I close the grey valve and open the third valve to drain the black tank again, followed by opening the grey valve to rinse the hose. It takes longer to type it than it does to do it.