Black tank shows full

[greyhawk]

Hi rv's my question is even when black tank is empty .
The 4 lights showing on the control panel shows tank full
what is the fix for this??? I have use the washer that goes on end of water hose and tryed rinseing that way but lights still show full tank are there some tricks of the trade that i can do that will work :d

[TXiceman]

This is a pretty common probelm fro the black tank. The area where the sensors are located get coated with gunk, TP and other stuff. One thing that works is to put about 1/3 tank of water in the black tank, dump a couple of bags of ice down the toilet, add some detergent and take off for a drive to slosh it around good. This will often clean the gunk off and get the sensors working again. If it is really bad, you may have to do a couple of treatments.

I always leave the black tank wet, that is a couiple of gallons of water and the tank chemicals during the season for use. In the winter, I may completely drain it, bit often do not since we seldon freeze in SE Texas.

Also, when you drain the black tank always have at least 1/2 or more full to allow it to drain well. DO NOT leave it open when parked and hooked up.

Hope this helps.

[AFChap]

In addition to rinsing well after dumping, the thing that is working best for me is to add a capful of Calgon liquid water softner to the tank after I dump. Actually, I can tell by the sound when I flush if the tank is getting anywhere close to full, and I know pretty much how many days we can go between dumps, but it is nice to have the lights confirm what I "think" I know...

[ghamblen]

I tried all the standard methods for cleaning the sensors in our gray tank but nothing worked no matter how many treatments we tried. It always indicated 2/3 full. I finally gave up and installed a SeeLevel II system. I have one monitor panel in the wet bay and the second monitor panel in the bathroom. It has been installed several months now and works perfectly. It indicates how full a tank is by displaying a reading between 0 and 100 percent. It monitors the black and gray tanks, the fresh water tank, propane tank and the battery at both monitor locations. Since one monitor is located in the wet bay I don't have to run in and out of the motorhome to monitor tank levels when emptying and filling tanks. I highly recommend this system.

[Doggy Daddy]

RV Holding Tank Monitor System | ModMyRVUpgrade to the SeeLevel System is the way to go.

[wa8yxm]

I have cleaned mine two ways.. Last fall, on the last trip of the season, I dumped, added 1/2 cup Calgon water softener, 1/2 Cup Dawn dishwashing Liquid (regular not anti-bacterial) and six gallons water.. Drove, about 70 miles, to my home dump station and dumped again.. Sensors read full, and full (of soap bubbles) the tank was.

When the bubbles popped the sensors showed empty

The oher method I use, which does not always clear the 1/3 sensor, is a pressure wash.. Valterra Master Blaster (I think is the model) I made my own..

Only seen that rinse wand in one store.. currently right behind me as I type.. but if you search you will find it I'm sure. May have to contact Valterra to find a dealer who sells it though.

[CrossCountryNomad]

It the six years of owning our current MH, the only thing I have ever done after dumping is add a cap full of laundry detergent, formaldehyde tank trement and a few gallons of water. The gauge works as good as it did when new.

BTW - I've never flushed out either of my holding tanks and never any problems.

[AFChap]

Quote:

formaldehyde tank trement

Formaldehyde is nasty stuff -- banned and/or illegal in many RV parks due to the damage it does to septic systems, not to mention the environment. If you think you have to use tank chemicals, there are plenty out there without formaldehyde. They will be better for the breakdown action in your holding tank too!

[Wayne MD]

Af Chap is correct about formaldehyde. Very caustic and a preservative of everything. Toilet paper won't even dissolve after use, because there is no bacteria to break it down properly. All solids in the tank is still solid only more so. Plus the smell of heavy use of formaldehyde in your tank can give you a headache or breathing problems. No wonder this stuff was banned. It belongs in chemical labs only. Not in your tank. Get rid of it.

[wilanddij]

Fill the tank about three quarters full with plain water (you will have to guess). Put in a little dishwasher detergent or some Calgon (or other water softener compound). Then add a bag of ice and drive around for a little while. That should scrub off all the stuff on the tank walls. Then dump it all and fill with new water and drain again. If it still indicates full, you have an electrical problem with the sensors.

[wa8yxm]

There is a complex test procedure I could outline for you, takes one long post. However try this Valterra Master Blaster Tank Wand - RV Parts, RV Supplies & RV Accessories for 5th Wheels, ToyHaulers, Campers

The picture is of no help.. Of all the tank flush wands I've seen this one,, Is actually what I made myself (or equal to it) This blaster shoots a single powerful JET of water which you can aim at the sensor wall. you twist and insert/pull (slightly) and blast the wall clean

About eight bucks