fractions of ounces no, an odorant won't harm the septic system in normal household use; however take care that some toilet bowl deodorizers and fresheners dispensed from the cistern or toilet tank can cause deterioration in rubber or plastic parts in the toilet flush and fill valve components...
As you begin dumping your black tank, you’ll begin rinsing with your black tank flush system. Close the black tank valve and allow the tank to fill a little, then open the valve again and watch your clear elbow. If the water isn’t running clear yet, repeat the process —close the ...