HELP! Black tank Clogged

If you use the cap w/ garden hose nipple you'll need a female-female hose. I use an old one I saved off DW's washing machine after I replaced them on GP. Be sure the TT valve is open before you turn the water on, else you'll blow the drain pipe and / or valve.

Since my sewer cleanout is in my front yard and can be reached with a sewer hose extension I back flush my gray and black tanks before putting the TT away for the winter.