The toilet IS the black tank. Whatever you put down the toilet (water, chemicals, wee-wee, doo-doo) gets pumped back up to use to “rinse” the bowl. Other than a vinyl flap, there is no valve that separates the “tank” at the bottom of the toilet from the bowl, which also has no water in it.
Some people use the recirculating toilet with no issues. Others don’t like the recirculating toilet. I never really had any issues, I just found it to be a gross little device knowing how it works. There are several options to swap out. If you want a real porcelain toilet with freshwater flush and a small blackwater tank, search “SeaLand” here on this forum. That’s what I swapped out to, and it’s some of the best money I’ve spent on my TrailManor. You can get the toilet from Scamp Trailers at
https://www.scamptrailers.com/produc...raveler-toilet or also search “Poor Man’s SeaLand” for a build-it-yourself option for about half the price (second two photos).