towpro wrote:
if on a site with sewer, we hook up and pull the gray tank so it drains all the time, but let black tank collect.
than a day before I leave I will shut the gray valve so I have something to flush the hose after I drain the black before leaving.
One of the mods Dad had me do to his 5th wheel was add a small drain about 3/4 up on his grey tank. Open 1 valve, could drain thru hose bib out to bushes, where allowed. Open another, and tied back into stinky slinky. This way he had 3/4 tank to run out behind the black.
If the grey got full before he planed to leave he would bucket some to black