[Richard and Rhonda]

Lee,

Look carefully at how that bypass is plumbed. In one config the bypass valve is actually closed and the main valve open. That config on mine lets the grey water run out the slinky and the black water goes into the tank. If you want the grey water to go into the tank and not back up in the shower, the bypass valve (on mine) is actually open. It was counterintuitive to me at first.

I can assure you that the shower will not drain if it's configured the wrong way :-)

Like Tuga, I find the one tank arrangement is easy to manage. Yes, having a sep gray water did make washing the hose easy. These days I use a macerator, and the hose is super simple to rinse.