with most black tanks and most situations, needing a tote tank isn't needed.
it's the gray tank that's going to need it way before a black tank.
unless you're staying in one place, without sewer hookups, for more than a week or have a small black tank, you'll easily be able to dump the black tank at the dump station when you leave.
but the gray tank is a way different storage. too many people worry about the dreaded black tank when the gray tank is the one to worry about.
i have a tote tank and still have never needed it for the black tank.