grey tank

There's a question we haven't heard before. Everyone has this problem.

Some have a small set screw on the tank monitor inside that you can try to set the level. As the sensors age they stop working right. We have seen some that different work on the show room floor.

They're all wacky, I never even look at it.

Put some Dawn in the all your tanks drive around and you won't have a problem in the future. I always Dawn the tanks on the way home after dumping, no lingering odors or residue.

About the only thing you can do with a grey tank sensor is to dump the tank completely. Then add a few gallons of clear water, a bit of dishwashing liquid and maybe some bleach and take the camper for a drive. The goal is to let the water slosh and pound on the sensors (and sides, top, and bottom of the tank), and wash free, or break free any scum build up on the sensors. If this does not work, then your next avenue will involve taking something apart to clean or replace or modify existing devices.

Get one of those scrubbing bubble characters you see on TV and dump them in the tank. Let them out when they are done. :) Remember what you're putting in those tanks. As the scum dries on the sensors they can't give you an accurate reading. The gauges are put in as a "feel good" item when you're looking at purchasing a coach. No one makes a gauge that is accurate for very long, if at all....Dennis

The problem is not with scum on the sensors but with crud on the tank walls that is wet and fools the sensors. This proven by the fact that the same problems exist with external sensors that are on on the outside of the tanks. They usually work with more crud on the tank walls than the through the wall sensors but will still give inaccurate readings if the crud build up is bad enough.
Anything you can do to clean the tank walls may help especially if you are a weekend user and not a full timer or extensive user. As a full timer for 11 years I never found anything or any product that worked (I had external sensors). I ended up just marking the calendar and dumping every 10 days.

Just ignore it.

Look on the bright side....it's 3/4 empty.