Black water tank light says 2/3 full after draining

I always keep in mind that we are talking about a sewage holding tank. It will never be squeaky clean.

The few times I have had an odor, it came from the roof vent pipe and an unfavourable wind.

I tried the ice because it's was cheap, it worked until the next trip.

We do a lot of sight to sight camping and find it best to let the tank slosh and dump when it is nearer to full. We do use the typical tank treatment elixir.

We also have no issue with using the CG wash house to save water and tank space.