Beginner sewer question.

First, what is the name of these devices that hold the waste? They are called "HOLDING" tanks, they are designed, and engineered to HOLD there contents until full, then flushed! That goes for both the grey and black HOLDING tanks! When preparing food, and washing dishes, solids will get into the tank, the same logic for black tanks hold true for the grey tanks as well! And the grey tanks can smell worst than the black one! Use the grey to flush out the line after dumping the black tank, and you will be happy. Use plenty of water when flushing, I know we have all been told to save water, but in an RV you need to use enough water, not only to flush, but to ensure you don't get a build up in the black tank! A couple of posts back Ron gave some good info, except I have to disagree with one thing he said! ½ cup dishwashing detergent, before leaving, that is way to much detergent! And it will result in soap scum build up, that will effect the sensors. I use this method, after dumping both tanks, and using the rinse on the black tank, I make sure I have 5 - 7 gallons of hot water, I get this from the shower and fill a bucket, then I do the following, 1 bucket warm water, ½ cup calgon water softener, and 3 drops dawn dishwashing liquid. Flush this mixture down the toilet, break camp and go. As stated the drive will slosh the mixture and help clean the tank. No additives, ever needed, no Oder, no problems! Good luck!