I then took out the table leg holder and drilled a 1 inch hole in the body brace where the table leg was installed. I then installed a 2 inch coupling and a 2x3/4 female pipe thread reducer then underneath I screwed in the 3/4 galvanized tee and ran a length of pipe to the holding tank and used a pipe to barb fitting and ran hose to a tee into my sink drain.
On the bottom of the sink I used 1 1/2 threaded to straight fitting that goes into a 1 1/2 x2 inch reducer which is removable both from the sink and the coupling in the floor .
I can put the leg holder back in when the holding tank is empty and when tank is being used I put a boat plug in it to stop holding tank smell and cover it with a rug.