Question about Black Tanks and full timing

Keep black closed until it is time to dump.

True fulltimers know better. He's just living in portable housing.

not as critical if you have a black tank flush and periodically spray it down, but yep, I wouldn't do it.
bumpy

Yeah, not a good idea

He either mis-spoke, you hear him wrong or he is not doing it right.

Chemicals......I agree with him. I don't use them. Tried them but didn't find a need for them. If RV seals, traps, AAVs, vents-----odor barriers/controls are functioning them chemicals not needed. If those design features aren't working them you smell chemically treated poop.

Grey waste tank.....OK to leave open but I don't because grey tank can have crud (skin cells, soap scum, food debris, oils etc) and I prefer to dump tank when full so they stuff gets flushed out

Black tank.........only time that drain valve should be open is when dumping full tank and when using built in tank flush system.
NO poop pryamids for me!!

You'll hear all kinds of arguements for and against treatment, it's a personal choice. As far as leaving the black tank valve open.....don't do it! You'll get a big pile of hardened solids on the bottom of the tank you won't be able to remove.