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How To Calibrate RV Tank Monitors

How To Calibrate RV Tank Monitors

 

Since we’re sometimes pretty serious boondockers (that’s camping without hook-ups for you RV newbies), we want to know the exact levels in all of our holding tanks – fresh water, gray water and black water – and our propane level too.

We have a fresh water capacity of 105 gallons, 65 gray and 45 black. The limiting factor for boondocking is always the gray tank. We can easily spend 7 days out in the desert, with both of us showering every day, cooking every meal on board, doing dishes etc. If we know we’re going to want to stay in one spot longer, we can make it up to 10 days by being REALLY frugal with water. When the gray tank is full, we always have about 1/4 tank of fresh water left, and the black tank usually takes about two weeks to fill.

A key part of knowing how long you can stay in one place without hook-ups is knowing the levels in your fresh, black and gray tanks. This video will show you how we calibrate our tank monitors so we always know where the levels are. Tank monitors vary by make and model, but this will give you an idea about how we calibrate our Newmar monitors.

This is not something that needs to be done on a regular basis. We calibrated our tank monitors shortly after purchasing our motorhome, and have never needed to touch them since.

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Glen Williams

Thursday 3rd of August 2023

I have a 1996 Newmar Mountain Aire with the exact monitoring panel that you showed in your video. I managed to catch the wires leading to my gray water tank sensors and pull them loose. I reattached them with adhesive backed aluminum ducting tape and I get a reading up to half tank but nothing after that. Do you know what sensors are compatible with this panel. I like the SeeLevel sensor system but don't want to have to replace all my sensors, especially the black water tank as I don't even know where they are. I like the panel I have and would like to just replace the sensors if I can get them.

TheRVgeeks

Thursday 3rd of August 2023

Hi Glen. In all likelihood, your black tank's sensors aren't all that far away from your gray sensors... usually Newmar places the black and gray tanks close together (i.e. often side-by-side). So, if you CAN get access to them... upgrading to SeeLevel sensors will definitely improve your tank monitor accuracy. Although, aside from accessing the tanks and existing sensor wiring, you'll need to retrofit the smaller (more square) SeeLevel display panel into the longer, more rectangular spot the old display panel occupied (we used a piece of black dashboard plastic we picked up at an auto parts store and use it to overlap the old hole and cut into it for the new one).

Assuming that none of the above has persuaded you to want to tackle that much work 😉😂, your best bet is likely to give Newmar a call and see if they can supply replacement sensors for your system. While they may not be EXACT replacements, they likely will offer the same functionality (1/4, 1/2, 3/4, Full) readings and will (hopefully) work directly with the existing display panel.

On the other hand, if you DO decide to go ahead with a SeeLevel upgrade... we LOVE our system... and we have a post about it here: SeeLevel Tank Monitor: Upgrade Your RV Holding Tank Monitors

Tim Stryker

Wednesday 6th of May 2015

Ok, thanks I'll try the dishwasher soap. Would that work as well for the black tank, assuming it was empty to start with?

TheRVgeeks

Wednesday 6th of May 2015

We've used the same method in the black tank (yes, empty it first lol), and we like the results. Give it a try.

Tim Stryker

Tuesday 5th of May 2015

What if there are no small screws for calibrating the indicator lights for tank levels. I have a Salem 23 foot TT and the indicator lights change levels all by themselves. I can empty my black and grey water tanks at the campground and have the lights show "full". And then when I get home, the lights show empty. Any ideas about that?

TheRVgeeks

Tuesday 5th of May 2015

Hi Tim. Not every system has those handy little adjustments screws, but if you're leaving the campground with one level showing, and then arriving home with another level showing, it isn't likely a calibration issue anyway. A more likely problem is that the sensors might need cleaning. You can try this method and see if it works: https://www.thervgeeks.com/plumbing/gray-tank-sensor-cleaning/

If not, you might consider stepping up to a higher-end monitor system like See-Level, but of course that involves some cost and installation.

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