New Here - ??? regarding sensors and black Tank

[GinaJeremyK]

Hi,

WE are new to the Part time RVing and own a 2007 forest River Flagstaff. We truly love it and we have been able to fix the little things that have went wrong since we bought it in SEpt. It has a brand new frig so that best not go out any time soon. However the last few trips we have noticed that our sensors aren't working correctly. We fill up with clean water including the hot water tank so we have enough for a week. before we leave parks we dump everything empty.

so this trip, we have noticed that the black tank continues to read full when we know its clearly not, but our galley and grey tanks are reading 2/3's full and we barely have used water. Our Fresh tank will show 1/3 full when we barely have taken any water out. Is this normal that sensors are just not working, should we look at replacing them? we cleaned out our black tank and it didn't help the at all. we also cleaned out the grey/galley tanks which didn't seem to clean the sensors. I can understand the black tank showing odd but not the grey or fresh water. its also odd that we added 14 gallons of fresh back into the tank and it showed 2/3 full and after a small sink full of dishes it read only 1/3 full that would mean we would of needed to use nearly 10 gallons and we no way used that to do the dishes ( filled both sinks) no other water used.

Allso i just read that you should nevery fully empty the black tank out? can i ask why that would be?

Thank you for the response as we take on this new journey as RV owners! i hope one day to upgrade to a new bunkhouse model of 5th wheel. Just not right now. we want to get lots of use out of this one!

[rsdata]

many many post here on faulty or toilet paper covered black tank sensors...

do a little Goggle search on black tank sensors and you will find enough reading for a week...

however the short answer is that often TP and other "solids" cake on the black tank sensors and make them read full when the tank is empty... many people add borax, calgone, Dawn water and even sometimes dump a bag of ice cubes to scrub the inside of the tank while driving down the road...

personally we don't put TP in the tank preferring to use a small waste basket in the bathroom that is emptied into the dumpster often...

[bikendan]

Never rely on the holding tank idiot lights.
The B/G level lights are notoriously inaccurate, especially on older trailers, since they've had years of usage.

[vmfa]

Originally Posted by bikendan

Never rely on the holding tank idiot lights.
The B/G level lights are notoriously inaccurate, especially on older trailers, since they've had years of usage.

Commando tank sensor cleaner enzyme works?

I finally resolved my black tank sensor problem that's showed 3/4 full even when emptied.

I've sprayed down into the tank wiith a wand to no avail.

I've never seen this product anywhere but saw it in the campground store and thought what the heck

I drained the black tank. Refilled it 90% full and I cut the bag open and poured the stuff in the toilet and then filled the tank 90 percent full.

Let sit 24 hours and drained.

Sensor now shows 0% full.

I highly recommend this product it really works.

[vmfa]

You can find it on Amazon by searching Commando Cleaner

[GinaJeremyK]

Thank you! we had seen it too.. and thought about it but wasn't sure.. We will not try that.. we are finding that our GREY Water tank does the same thing and our Fresh water tank doesn't read correctly either. i don't want to use that cleaner in the fresh water tank but would you use it in the GREAY Water tank?

we will definately try this!!!! I appreciate it. we are diligent about emptying our tanks after every weekend trip and if we have full service, we only dump every other day vs letting it drain straight thru.

[vmfa]

I see no reason why you could not use it in your gray tanks.
Usually in the black tank toilet paper and crud get on the sensors and doesn't come off causing them to read false.

My gray tanks, one is tied to the kitchen and the other to the shower and sink in the bathroom.

I suspect grease and kitchen sink crud could false you sensor in that tank and maybe body lotion and shampoo residue on the bathroom one.

Its very in expensive and I was thrilled to death cause I been fighting this issue for a year and was so happy to see it indicating empty.

I cannot see why anything would cause a fresh tank sensor to read bad unless you had a lot of hard water and don't use a filter on your water supplying the fresh tank. Its possible you could have a lime residue building up the fresh tank sensor.

Try it on the other 3 if it works you could try it on the fresh Just be to fill and flush it several times. We don't consume water from the fresh tank and buy gallon jugs of water for consumption.

[B and B]

I use my tub shower and Tide. I soften the water I put in my Fresh Tank. Put Tide in Toilet, fill with hot water, repeat many times before dumping. There are many bubbles due to soft water in the tank and this cleans the sensors! Flush with tank flush at dump station.

[SailorSam20500]

As noted by everyone, tank sensors are notoriously inaccurate, Adding to the issue, the wires used are skinny and could easily be compromised. From what I've read, probably the most accurate setup is the SeeLevel II RV Tank Monitor System. The sensors are outside of the tank, so not subject to contamination. However, the system is expensive - so I'm just going to make do with what I have. FWIW, I use the geo-method of tank management using liquid Calgon and Dawn. So far, so good.
I'd suggest dumping your waste tanks, add about 5-10 gallons of clean water and a 1/3 cup each of Dawn and Calgon. Then head home or to your next campsite. A hundred or so miles on the road may slosh around enough to clean off the sensors. I wouldn't do this for the fresh water tank though...

[larry2c]

Here's a question/thought on your fresh water tank gauge. Ours was wired incorrectly and if you filled the fresh tank from empty and watched the lights you'd see that it went from empty to 1/3 and then jump to completely full. I redid the wires to the sensors and now it works perfectly (or as perfect as these type of sensors work).