For those that are new to RVing…
Factory-installed tank sensors are wholly inaccurate. Previous polls on this site also substantiate this information. Deposits of paper and “other” things get stuck on the sensors. A perfectly empty tank can still read full as a result. Some folks have tried other methods such as dishwashing soap, ice, hot water, and other methods that may work with mixed results.
There is another way to know your tank is full (or close to it) besides using sensors or sound. “Sound” is also a good indicator, but in addition to that method, the closer to full, the more it smells (even if you use chemicals). You’ll want to dump for sure when you can’t take the smell any longer.
“Splash back” is another indicator. Air will get trapped and when you flush, it bubbles back before it goes down.
If the three methods (sensor, sound, smell) fail to warn you of impending doom, you’ll probably get to see a brown liquid coming out at the base of the stool at the floor flange. From there, it will ooze on the floor or into the basement. At that point, you certainly can’t miss it.
There are external sensors that tend to do better than the internal sensors. You can purchase them after-market and use the wires directly from the internally mounted sensors.
We are full-timers. Our black tank is 52 gallons. Without being conservative, we can average about two weeks for two people – sometimes three weeks if we are a little more conservative before we require dumping. Maybe this will help you gauge when a dump may be pending (no pun intended).
Thanks for the tip, TravelingMan!
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