max flush button you should get some water entering the bowl, then the motor will run which evacuates that water and the process repeats itself two more times. You can set the time the and amount of water that enters the bowl on each flush. Are you getting the three cycles? Is there enough water in the bowl for the macerator motor to 'grab"? You might need more water then it's currently set up with. Try running some water into the bowl from the shower hose and then doing a full flush and see what happens. It shouldn't make any difference using fresh or salt water unless you are not getting enough of that kind of water. Try switching to fresh and see it the bowl fills to a higher level.