Carrying a Portable Waste tank

We use both of our tanks, but haven't filled up the black one yet and needed to empty while we were boondocking. The gray is another matter though, and so we just bought one of those 6 gallon jugs at walmart (tall skinny, greyish blue) and keep it in the shower after rinsing it out. We also bought a blue one in case we need to add water without a spigot near by. they just store in our little tiny tub perfectly.