Good Morning folks,

I have a 1984 Shasta Roadmaster.  The panel that should tell me the levels of my holding tanks isn't working correctly. I am not sure if it is the panel itself or the sensors in the tanks.  Previous owners didn't know either.  I don't want any unpleasant surprises so, how often should I dump my black tank? I have been dumping it once a week to be safe but, I understand it should be 2/3 full before dumping. How can I tell I am at a good level to dump? Thanks for your help!


Tags: Holding, dumping, sensors, tanks

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I'm not familar with your Shasta display, so don't know about the panel.  To clean the sensors, dump some Rid-ex in your toilet, look down the open toilet with a flashlight and fill the tank with water to 3/4 or so.  Then drive around to allow the rid-ex to slosh around good.  This should clean the sensors.

Good Luck,


Shasta models used in tank level sensors,, Richard had the perfect solution,, Rid-X and drive it around a bit to slosh the tank and *clean the sensors. (with 1/2 to 3/4's). This usually does the trick and if not,, the sensors corroded up on you.

F.Y.I. Don't ADD any BLEACH product with any other cleaners in your waste tank, That will cause a deadly gas.  

Thank you both for your input.  I do know bleach is a no-no.  Is there another alternative to driving around? I have a tank cleaner that goes down into the black tank from the toilet.  It spins and sprays water. Looks like a fishing pole.  I use it every time I dump the holding tank. But, I have never used rid-X. 

If my tank sensors are corroded, whats the chance of all tank sensors on black, grey and freshwater  being messed up? Also, is there an aftermarket panel that'll work for my classic class c?

Thanks again for your help!


Upon further examination of the exterior of my black and grey holding tanks, I have noticed I have a wiring nightmare.  Most of the sensor wiring is corroded or missing.  So, I won't be using the panel any time soon.  I will be using the flashlight method of checking my levels.  This is brings me to my original question, when is a good time to dump the holding tanks? When I reach 2/3 full or weekly? I have heard both. Thanks!

i'd vote for no more than 2/3rds full and not too stinky. however, don't dump when there is little in the grey water since it is the only thing that flushes the black.  black first, then grey to flush.

disposable rubber gloves, paper towels and hand sanitizer kept handy. don't go down the road with full, and very heavy tanks. you're already carrying enough weight in any rv. just my experience.

I go half to 3/4's and ALWAYS dump before moving/traveling (except for maybe a couple gallons in to slosh a little, and keep the tank wet.)

Another piece of advice when traveling Don't fill your fresh water tank full thinking you will need alot of fresh water. Water weighs approx 8 lbs per gallon.I usually keep about 5 gallons,, enough to flush toilet and wash hands. I then fill the tank pror to pulling into a campgraound where no fresh water hook-ups are available. 

Thank you folks again for your advice. I will be "eyeballing" the level on the black tank.  I do keep the grey water tank closed and open only to dump so, I always will be able to flush the hose after dumping the black water tank. My freshwater tank is not a problem, because my pump only works when it wants too.  I have some wiring to chase on a later day.  Thanks again!


Garnet technologies in granbury Texas makes some tank sensors that stick to the outside of your holding tanks and are wired in parallel. The display is easy to read and is easy to install. Goggle them to check it out. They are excellent.





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