portable holding tanks

I have the Barker 42 gal, 4 wheel tote. I put pnuematic tires on it like many here have, and it works great. The only problem I have is the height of the inlet relative to the trailer plumbing. Not much you can do about it but milk the hose when necessary. Macerator pumps and the like eliminate that. I don't use it often, but when I need it, it's much easier than breaking camp. Both my tanks are 40 gal, so one trip per tank and done. Usually only need to empty the gray. We can go a full week on the black.