Inaccurate holding tank readings?

I imagine the tank could be so dirty that they don't read. Another thought is to check that the sensor is stuck tight to the side of the tank. I don't know how they work, but I imagine a loose sensor strip could cause a false reading.

What puzzles me is there are no probes inside these tanks on the newer MH?The old excuse was [paper gets on them etc!!!!I don't think there is any contact between the sender and the internal of the tank.It is just a small unit on the outside of the tank?Maybe I don't uunderstand how these new rigs work but all indication is that nothing goes thru the wall of the tank?on't know hwat those Horst[sp] units are.Thanks for the replies If there is nothing into thru the tankwall not sure what the ice cubes will do to help but have heard of that for long time but never tried it.Old system could insert as tube into tank and spray usually helped for a while.!Still found the di[pstick most accurate if yuou could get at the top of the tank.worked for 15 years on my Eagle!

Ka Ron wrote:
Here is a tip for cleaning tanks.

Works pretty good.

Clean Black Water Tanks

Did this once. It didn't show full after that bur it still showed 2/3 full. Next time I dumped it showed full again.

I installed the Horst Miracal probes about 6 years ago and no problems since. Accurate tank levels.

Here is a tip for cleaning tanks.

Works pretty good.

Clean Black Water Tanks

It don't make no dif.mine worked for while , and like most RV junk gets on the senors, and Wala, so I got a idea to watch exactly how much stuff goes in the tanks. Wow works for me. And now it's all happy-campi g

Our sensors measure in thirds, and have found them pretty useless. Experience has also taught us that after 4 days of showers and minimum dish washing, the gray tank is full. Like the previous post....if the water appears in the shower.....it's full! The black tank takes a few more days to fill, rarely a problem. Once when the gray tank sensor said full, we poured a few more gallons down the shower until it overflowed, and found we could easily have had another shower at least!

Darn I just installed the Horst Miracal probes. Hope they work as advertized, But like Ka Ron, I usually dump every Sunday as we stay in one spot for months at a time. Both tanks are usually kinda messy after 3.5-4 months so when we move from one place to another I load the tanks with soapy water, 1/2 cup liquid soap and 10 gallons water. After a few hundred miles I'll dump that and re-load 2-5 gallons just for starters.
Cheers

When the water does not drain out of the shower. Tank is full
When toilet water does not go down. Tank is full

Seriously, that is a common problem. The only thing we figured out was with the grey water we are good for 4 days with showers and then we drain tanks.

Our gauges are like yours, always full