newbie questions on black water tank and campgrounds

I rarely get any black tank smell except occasionally when it's over 3/4 full. Even then, It's rare. One tip I've found is to shut off the roof vent fan in the bathroom when flushing. With the fan on and the bathroom door closed, you create negative pressure in the bathroom and the fumes in the black tank get drawn out when the flush valve is open.

But again, we're not talking massive odor at all. I use some enzyme and Odorlos.

Ray