View Full Version : Black and grey water tanks show full when they are not, how do I fix this?

09-21-2018, 10:03 AM
So even when empty the black shows full and the grey shows 3/4 full, which is not ideal.

I understand 'stuff' can build up on the sensors and cause this, but how does one fix that?

Is there a better system I can install or upgrade to which will give me good, reliable readings that isn't susceptible to this sort of thing? I'd like to know I can always rely on the readings and not have to 'remember' when they might be full.

09-24-2018, 03:29 PM
after emptying the tanks fill them full of fresh water
then open the drain valve and let it flush out whatever
is in the tank. One tank at a time.

This usually works for me.

09-25-2018, 05:44 AM
I have a cougar 2019 5th wheel with incorrect levels on my in-comand system.
One time my #1 gray tank showed 1/2 full. And it was full. I could hear bubbling in the shower drain.
Fresh water, filling it up and it was only showing 2/3 full. Water was coming out the fill nozzle.
Black tank. Your right, I don't take that chance and dump at 1/2 . With a good rinse.
I do not like running back to the dealer for this and every little problem. I feel it should be an easy fix for the owner.
I am thinking of filling my tanks with a measured amount of tank capacity water and see what it shows on the read out.
Any ideas?

09-25-2018, 09:52 AM
When my tank reading lights were showing wrong levels I would use the Flush King unit to back flush the tanks. I also would open up the basement side panels to expose the plumbing cleanout cap. Removed that cap and used my made up wand to put water pressure into that opening. I would force out the gray water holding tank "stuff" that was clinging to the sides of the tank. Tank readings worked again. About once every couple months or so I would do this where the park had terrific water pressure, made the job easier and faster.

09-25-2018, 01:08 PM
Most manufacturers use the problematic screw thur the sidewall of the tank system that always fail. I am picking up a new Jayco Pinnacle this week and one of me first mods will be to install a SEELEVELII monitor system made by Garnet Industries. Put one on my last RV and it was great and very accurate. Never had any problems. You do need to access the side of each tank and apply a special sensing tape on the outside of the tank. I then use a couple of the old sensor wires to connect to their panel. Not a easy install, especially if your not comfortable digging into the bowels of your unit.

09-25-2018, 09:14 PM
Another way to help clean the sensors is to drive between locations with about 1/3 full tanks with some sort of cleaning product added. In my previous Suites with the regular in-tank sensors, using bleach some times or Dawn some times or Cascade sometimes almost always resulted in good readings for some time, only to re-occur at a later time.
No longer a problem with the SeeLevel gauges in the '15 Suites.

09-26-2018, 07:56 AM
Put some dish soap a gallon of water and ice in empty tank just before you are ready to move. Towing will cause a scrubbing action of the ice and the dish soap will help break down the scum on the sides of the tank.