Curb side flush out connection for hose ?

[Bob & Peggy Standeford]

I just found a hose connection on the curb side black/gray water tank. It has a tee on it with a tube that goes to the bottom of the tank. It now looks like a brown stained sight glass. Is this something that's on each tank on is this someone added to my tank? Has anyone used it as a flusher for the tank? or any thing else. Thanks for the info.
Bob and Peggy

[rheavn]

My coach has the same set up. I had to replace the clear hose as mine too was stained. Available at hardware store. When the electronic monitor system doesn't work right the sight glass lets you know exactly how full your gray/black tank is. I just got through washing out my tank for the season. Just hook a hose up, open the valve and flush away. Don't forget the hose is on as you will flood your coach once the tank is full.

[Bob & Peggy Standeford]

Thanks Steve, It's nice to know these things before I try them on my own. You never know when you'll do something stupid like flooding the inside. I didn't think about buying a new hose that's a good fix.
Bob & Peggy,