Welcome to our forum.
I'm not sure what rinsing off has to do with it as it only happens when we put the diverter in one location? One position it's fine, another position and we get foam/bubbles turn it back to the other position and the foam/bubbles disappear?
I was told that my Prodigy did not have an air pump? It is the diverter handle located right were you step into the spa. It gererates a lot of foam/bubbles and then you switch it over and the foam/bubbles disappear?