DunellenGuy wrote:
...
1) ... If not, how do you hook up when you get to a campground?
2) What are the advantages and disadvantages of this multiple tank system?
Jeff
Question 1:
There are a couple solutions.
A: You dump each line one at a time using the same hose, moving it from one RV sewer connection to the next.
B: You get extra hose and connect a hose to each sewer outlet. Then you connect them with a series of these:

Question 2:
A. If one tank is not full, you do not need to empty it, just empty the one that's full (or the one you want to dump).
B. The advantage of multiple tanks is, they are usually smaller than one large or two large tanks. This means, if you take along a portable (wheeled) tote, you an fill one tank at a time without over filling the tote.
C. Multiple tanks, dedicated for one purpose will prevent black water from blowing into non-black water tanks. (There's been lots of debate over the years on these forums about cross-contamination????? if that's what you call it). But this is one way to prevent this from happening.
D. More smller tanks will also distribute the weight (if full) over a wider area of the camper, making the weight distribution a bit more even on all tires.
E. In smaller campers, or small Class B's or C's, small tanks may be the only thing that will fit, and can be tucked into smaller places, utilizing dead space under the floor and between the RV frame more effectively.