What tank levels really mean (195RB gray tank)

[MontanaRick]

I know many give up on/ignore the tank level meters as completely unreliable, but others do use them. We avoid having solid matter going into either the gray or black water tanks (so far), and they seem to work for us, although what the actual levels mean has been questionable. I decided to test our gray water tank, since it has been our limiting resource (long before black water fills, before battery gets to 50%, and a bit before fresh water runs out). I tested by adding one gallon at a time and checking the meter.

Here are the results for our 20 gallon gray tank:

1/3 = 7 gallons (blinked a bit at 6 gallons)
2/3 = 11 gallons
Full = 17 gallons
Backing up into tub = 20 gallons

So the 1/3 was on, but the others were really misleading. This also agrees with our experience that it was going from 1/3 to 2/3 way too fast and that there was certainly room left when it reads full.

No doubt YMMV! But thought others might find this mildly interesting.

[JFlightRisk]

What the sensors read depends on where they spaced them on the side of the tanks. I've been under ours, and it looks like they kinda eyeballed where they drilled. Definitely not evenly spaced. Our gray tank can read full, and still good for a couple more days.
We flush out the black tank with a wand every time we use it, and so far the sensors still work after seven years.

[RetiredOne]

Here are the results for our 20 gallon gray tank:

1/3 = 7 gallons (blinked a bit at 6 gallons)
2/3 = 11 gallons
Full = 17 gallons
Backing up into tub = 20 gallons

I see it as two different ways...

First, depending on if your coach is level (or not) the liquids flow to the low side. If the low side is the sensor side, you'll get higher readings than the actual levels.

Second, they might have built in a margin of error on purpose when they installed the sensors. IE: tank reads full at 17 gallons but really has space for a few more... just in case... Kinda like your fuel tank, it will read empty but still have a gallon or two left to get you to a gas station.

[stateboy]

My black tank meter still seems to work well after 1 year of ownership. I just looked down into the toilet without the water pump on to get a visual and it seems to be rather accurate to what I read on the meter.
The gray tank meter quit after one year and reads full all the time. I just estimate as to when to empty. If I've miscalculated, the bathtub will back up and tell me that it's time. One of these days I will try one of the concoctions mentioned on the forum to attempt to rinse the sensors clean and see if that helps.

In the meantime, camping continues, even if it is raining a lot this year in Michigan.

[RogerR]

My grey and fresh water sensors never worked worth a darn. As I have very limited fresh storage I just dump when I can or have to. Bottom is covered so no chance to get under there.

I intend to add some stuff (to be determined) the next trip to see if I can clean up the grey.

I just lift the bed and look at the fresh tank with a flashlight.

[Atlee]

Originally Posted by RogerR

My grey and fresh water sensors never worked worth a darn. As I have very limited fresh storage I just dump when I can or have to. Bottom is covered so no chance to get under there.

I intend to add some stuff (to be determined) the next trip to see if I can clean up the grey.

I just lift the bed and look at the fresh tank with a flashlight.

I just got my J Flight 23RB back from the dealer because the fresh water wouldn't register at all. No light, no nothing. Turns out a ground wire had come loose.

I know those monitors are notoriously inaccurate, however I figure of all of them, the fresh water monitor should be most accurate since it shouldn't have any foreign matter in it, except for clean water.

Even this wouldn't matter so much, except my 23RB came with the double fresh water tanks which gives me 84 gallons when full. I never need but 1/3 to 2/3 of that when I go out, but the only way I knew I had enough was fill the tanks completely and that is a lot of extra weight I didn't need.

Not as much problem with black and gray since I would be dumping every few days anyway.

PS: Good think I had the fresh water monitor repaired. The dealer found 5 clips holding the fresh water tank in place were broken.

Sometimes, I wish I didn't have the enclosed underbelly. Would be great to be able to take a quick look to make sure the tanks were secure.