Old-Biscuit wrote:
Why 2 separate tanks with separate drains........
Probably due to tank locations and not being able to have enough drain slope to connect aft tank to forward tank--------other items in way of routing piping, frame in the way etc. etc.
Just remember IF you change drain line piping.......it has to have enough slope so that debris/particles do not build up.
Its grey water , you could get a reducer tee and make the equalizer pipe 1.5 inch . You will have no wiggle room to connect the two together . You will need a rubber fernco