Keep the discharge seacock closed unless discharging. I also keep the raw water intake closed even thought it doesn't push water in when underway. Just another hole in the bottom I want plugged.
When you use it, open the raw water intake seacock so water can come in. You likely have a disc on top of the housing next to the bowl, turned one way is designed to pull in raw water (and also flush into the holding tank). The other way flushes without pulling in water (although residual stills comes into the bowl). When the tank is full or you just don't want that rotting in the tank, go to a marina with a pump out. The access plate for pump out is likely on the gunwale cap. They'll have a pump station with a hose that seals over the opening. Enjoy the show. I keep nitrile gloves and hand sanitizer in a bag on the boat for this. Alternatively, you can discharge offshore if over the right distance, as long as you aren't within a non-discharge zone. ONLY USE MARINE TP. The only things that should go into it: what comes out of your backside or bladder and marine TP. NOTHING ELSE. I had to rip open my tank and clean out the macerator twice before due to feminine toiletries in the system. Doesn't matter how seasoned the people are, they'll flush what they flush. I don't let anyone outside my family use it without me saying, don't put anything else in there!
