Nothing dissolves in the toilet because there are little bacteria working. A healthy black tank should be a seething cauldron of bacteria!
Just had an issue, knew it was going to be a problem when I hooked up. Rv park sewer is too high. solid's quickly back up and block drain as water goes through, have to lift hose at RV and keep lifting towards drain.
Looked in toilet with flash light, sure enough a pile in bottom of tank. filled with water and drained again, lifted hose from RV to drain. Filled tank and dumped again, lifted hose at RV to sewer and finally success.
