just bought my lance 845 last week, when i used it the first time the fresh water monitor showing empty but actually i had more than half of H2O in it also i noticed that the black and gray monitor only shows half even when i tried to fill it up with water. i know it is not the mineral contents of the H2O cause it never happen in my old camper.

For the waste tank I would get some emzyne from the hardware, fill the tank with warm water and add the emzynes. Let it sit for a few days and then flush it out. I maintain my waste tanks by adding detergent and pinesol between dumps. For the potable water tank, I would put in a couple cups of clorox, fill and let set for a day then flush until the taste is gone. For both situations agitation is helpful, like driving around on the road. JMTCW

thanks for the tip, i will try it this weekend.

The freshwater monitor seems to work fine on my new Lance 825, but the gray water monitor showed 1/3 full when I put less than 1 gallon in it. I had Lance check it, and then replaced something, maybe a circuit, and it now works better, but not as well as I believe it should. Lance told me that the truck must be absolutely level for an accurate reading. I have also found that the monitors are more accurate first thing in the morning, before anything is used.

Now if I need to know the water level at a more accurate level than what the monitor shows, I look at the water tank. For the grey, I try to stay aware of how much goes in it, and compare that with what the monitor shows. Plus I try to empty it whenever possible. It's possible that a truly precise monitor does not exist (just like you can't get a precise propane monitor).

Might want to check the monitor panel. My 1181 had all kinds of problems till Lance replaced the monitor panel. Bad circuit board.

Good luck