Black water - Grey Water ??

A far more accurate system:

A clipboard next to the throne where you put a check next to #1 or #2. Once you figure the number of checks...

Since RV is used difficult to tell how long those monitors haven't registered properly. Some RVers don't worry about them & some make sure tanks are empty every time. On the black tank some RVs have flush systems installed. If not you can make up a easy flush system or buy them from Walmart that go into commode with hose connected to flush tank. I made my own with 30" of 1/2 copper pipe. Valve & hose connector on one end. Cap on other end. Then drill two 1/4 holes into side of cap opposite each other. Works great. For grey I use a grey water treatment or some strong soap through kitchen drain. It may take a while to get them clean again. I make sure the monitor reads empty every time. It does take a little extra effort. Some thoughts. Keep in mind. The less grease & soap the less problems in the grey tank. JMHO.

Someone on here suggested the best way to "fix" them is to put electrical tape over the indicator lights! :B

agree with all the above the sensors rarely work on a fulltime basis for gray and black water tanks. There are all different methods to clean tanks, more importantly be sure to use plenty of water with each duump of the black tank it helps to carry waste out. then flush waste hose with grey water.

Thanks guys I was going to let the sink and shower run being I am hooked up in the yard and fill the grey was tank, can I just put the dawn etc down the sink drain or should I be able to access the tanks directly ? I could not see where to do that

You are finding out that those tank gauges are notoriously inaccurate. The water tank level is often correct, the black and gray water tanks not so much. You can try cleaning the tank(s) and that may clear the crud hanging on the sensor rod and make it work better for a while. A cup of water softener (powder) and a cup or two of Dawn is often used. Add 5 or 10 gal of water and let it slosh around when you drive.

There are more accurate meter systems, search in the DIY forum and you'll probably find mention of them.

BK

gages are very inaccurate, as waste piles up on the 'sensors' in the tank and shorts them, giving strange readings. My black tank in particular has shown half full for two years now.

Always drain the black tank first, then grey, as that flushes out the nasty material from your lines. Both tanks drain through the SAME exit point and through the same hose, which I think is a 3" hose. If I'm wrong, someone will be sure to correct me.

This site gives great info, particularly for the new person. Most of what I know, I learned right here.