Very interesting design. So it looks like if the flush/ overflow tubes leaked they would just drain down to the black tank instead of running over the floor. Genius.
How does the tank regulate pressure? I'm a little confused.
I did do a thorough cleaning as there were 2000 dead fly larve in that "airspace". Can all those moving parts be replaced without dissembling the two halves?
With this "two piece" design if full enough, is it possible the black tank could "slosh" forward and up into that area? Guessing maybe that's how it became so dirty.