Thanks Folks.
Many helpful hints. We camp in Provincial and State Parks only. No hook ups (only electric). Do my best to limit use of potty for night time and mornings. We also do not use the shower (so far!!) and dishes are done outside (still camping like we are in our popup!). Know roughly how much is going in both grey and black tanks due to how much fresh water on board.
Tank starts out empty according to lights then fills quick.
Again thanks. Will do a thorough rinsing and see if that does the trick. If we have the gauges might as well have them working.