I'm revisiting the thread to give a follow up to my case. The commode no longer burps and spits back. I finally had to use the fill the tank and let sit approach along with the use of some regular Mr Plumber drain cleaner. That seemed to do the trick. It cleared the partial blockage and it returned to normal operation. Since then I have been religiously adding 2 caps of halgon water softener and a heavy squirt of blue Dawn dishwashing detergent to the freshly dumped tank. In addition I have trained the wife to put water in the bowl BEFORE using it as well as cut paper consumption. I am still underwhelmed by the "bright person" who set the design where the down tube actually doesn't go straight down into the tank but crosses horizontally some distance. What the **** were they thinking?!?!?!?