Dumping the old tanks

[eaw]

I dislike stinky slinkies,nuff said.
We installed(me) a macerator pump,dumptastic Joann will even do the deed.
Permanently installed 1"flex hose with ball valve on end just hook to stand pipe open the "clean" ball valve,open the black valve and turn on the pump,when the black starts sending slugs of air open the grey,it "cleans" out the nastiest stuff and flushes the hose. When it empties the grey it will send sluggs of air pushing MOST but not ALL of the grey water.close the dump valves turn off the pump,done deal until the next time.
You can walk the hose to get all the grey out or close the ball valve and store the hose with minimal grey water trapped between the pump and ball valve.