We had a Thetford Aqua Magic V toilet.....all plastic. Worked perfectly for 8 years. Is the Thetford 300 plastic too?
The kids bought Mom the Dometic 301 for Motherís Day and I got stuck installing it. Mom wanted a porcelain toilet. The waterline attachment connector was on the opposite side than the Thetford and I had to add line and install an in-line shut off tap.
It was extremely tight fit to back wall, but itís in, and Momís happy.
Ken and Terry
2018 Sunseeker 2430S with Trekker cap
and only rarely pushed by our 2017 GMC Terrain toad (4 wheels down)
Former Georgetown 330TS owner for 10 years with more mods than I can count.