After I bought the 2025 Coachmen unit I started having problems with the toilet not flushing as well as the toilet in the former camper. Or should I say the build-up was more noticeable. The former camper never gave me a problem as far as the toilet. As DSurette
noted there could be a number of thing causing your problem. At home I mashed the pedal to open the toilet and peered down into the cavity with a flashlight and noticed that the tank was very shallow and still had stuff in it after dumping at the last camping. The old unit's tank appeared to be a foot or so deep but this one appears to be maybe six inches. I made me a homemade macerator out of an old garbage disposal to clean out the tanks and was really surprised at the amount of stuff in there although I dumped and rinsed at the last campsite. I have a place to dump into my septic tank at home so I could run all the water I needed to do this. It took, honestly, at least sic tank full of water, using the "water wand" stuck down into the toilet to get good clean water coming from the black tank. Then to my surprise cleaning the grey tank wasn't much easier. I wasn't completely satisfied with the homemade pump as the discharge volume over a 30 foot or so run was weak. I did buy the Flo-Jet macerator pump and it sure works better. I use a clear 90 degree elbow between the dump pipe and the Flo-Jet so I can see what comes out. NO, it's not pretty but necessary to assure a clean tank. I just went out last Thursday (today's Sun.) to wash the tanks out just because I had time and thought of it. I filled the black tank using the backwash on the Flo-Jet until the level in the tank looked to be about half-full. When I started draining the tank I couldn't believe all the live, white, little crawly critters coming from the tank. Lesson learned: DO NOT leave a tank thinking that it is empty. There can be enough rancid water in the tank to sustain some form of live vermin growth. I cleaned each tank until I had clean running water coming from them then put and estimated five (5) gallons of water into the grey and black tanks. Then I added some liquid insecticide and one pouch of dish washing stuff. Yes, I need to get more of the correct tank additive for sure. I happened to remember one story a camper told me a few years ago where he took his camper home, he cleaned out the black tank with the squiggle tank wand and drained off what he could on the ground at home which was his normal thing. Later he went in the camper for something and the mosquitoes ate him up. He found that the pedal had stuck on the toilet, the slide thingy was open and he had one of the largest mosquito crops in his area in his black tank.