Black tanks. How often to... dump.

Does anyone have a good rule of thumb for a good amount of time that's necessary (both minimum and maximums) in between tank dumps? We're going to be using our new "ship" for a couple days, on and off for the next couple weeks and I doubt producing enough... black water... to merit a dump based on volume and capacity. Should we dump regardless? Do people usually dump and flush after each trip?



I ordered a Sewer Solution and plan to use it, plus I have the tank flush hookup as well. Obviously I'd like to mess with this as seldom as often though!



I guess I'm looking for a "dump your black tank when it reaches 50 out of 60 gallons or every X days, whichever comes first."



Thanks in advance!