or marine heads more appropriately...since i want to elevate the tone
of discussion on this group let me ask a question.

a few years ago there was the 'princess of poop' (i think her name was
peggy) who knew ALOT about marine heads...

anyhow, i have an electric head on the boat which has a 3 gallon
tank. it's filled with water and deodorizer. when the head is
flushed this gets recirc'd through the tank. no connection to raw
water is made. however, there's a direct connection from the rear of
the toilet to a pump out port on the boat but i'm not sure if the tank
on the head can take the pressure of the pump out, so i want to
install a holding tank.

i'm looking at a 6 gallon polypro waste tank with 2 connections and a
vent connection. it looks like these waste tanks are USCG certified
(since there will be no sea connection).

so do i NEED a tank? is the 3 gallon holding thank on the head going
to take the pressure of a pumpout without blowing up?

if i install a polypro tank with no sea discharge is that legal for
USCG cert? (it seems it is).

any hints to ensure no unpleasantness?