Black Water Tank Gage

[live4thedash]

My black water tank gage always shows 2/3 or full even though I've emptied it and flushed it. What would cause this gage to not read accurately? and how can I fix it?
thank you

[jplante4]

Tvov wrote:

dieseltruckdriver wrote:
The easiest fix is to put a small amount of black tape over the readout. If you can't see it, it is easier to not worry about it.

This pretty much solves the issue!

Actually, they would need to leave the bottom green one showing for this to really work.

[Tvov]

dieseltruckdriver wrote:
The easiest fix is to put a small amount of black tape over the readout. If you can't see it, it is easier to not worry about it.

This pretty much solves the issue!

[dieseltruckdriv]

The easiest fix is to put a small amount of black tape over the readout. If you can't see it, it is easier to not worry about it.

[Community Alumni]

Our RV has sensors that stick on the outside of the fresh, grey and black tanks. These are proximity sensors and I would guess that they work in a similar way as a stud finder finds studs in a wall. This arrangement works great. The Black Tank circuit on the main board in the control panel went out, but fortunately the toilet sits directly over the holding tank so I keep a flashlight handy. Swapping sensor leads proved the problem to be in the control panel. Great system, only if it lasts longer than the warranty.

[live4thedash]

All good info to consider, thank you everyone!

[Tvov]

Another way to help keep the black tank clean is to dump dishwashing water into it every so often. We do this a lot as we routinely camp at sites without sewer hookup, and to avoid filling the grey tank too fast we wash dishes using a bucket and dump the soapy water into the toilet (which would be into the black tank). Just something to think about.

[DutchmenSport]

"Why do people want their black tanks to be clean inside?"

It prevents build up because the contents will dry out and turn hard. Then build up again, and again, and again. Over time, the tank will be full of noting but solids and rock hard built up 1/100th of an inch at a time (or more).

A simple method to keep the black tank cleaned out and spare the usage of water, if both your black and gray outlets exit at the same spot, is to get a Flush King style (3rd) slide valve with a clear section. Start by draining the black completely, regardless of how full it is or is not until noting more comes out. Then close the 3rd Flush King valve and open the gray tank and let it back-flush into the black tank. Wait 10 seconds and close off the gray. Then open the Flush King valve (3rd valve) again and a BUNCH more will come flushing out of the black tank. Repeat 3 times, and finally rinse the hose with the remainder in the gray tank. The back flush method saves water, cleans the black tank, and pulls MUCH more out of the black tank that would have been destined to just sit there and dry out!

[jplante4]

This issue comes up here on a regular basis (like, monthly). Stow the OCD and ignore the gauges is the usual advice. I have a black tank flusher and can look directly into the tank. Every 4th dump or so, I dump and flush, then refill with the flusher to 1/2 full, then dump again and keep doing that until the flush water comes out clear. I look into the black tank through the toilet and I see the bottom of the tank. The gauge lights read 1/2 full. My gray tank gauges have never indicated less than 3/4. I've done Geo and Simple Green and it makes no difference.

SO... stow the OCD and ignore the gauges.

[Tvov]

I consider the tank gauges as more of guidelines rather than rules.

Most campers are setup so that the toilet drops directly into the black tank, so you can just shine a flashlight down there to see how much room you have left. Remember that a lot of the tanks are wide but very "shallow", not very deep - even if it looks almost full, it may be only half full.

With experience you'll figure out how your tanks should look.

[Sport45]

Seeing all the trouble with blank tank level gauges makes you wonder how the generations before us coped. They didn't have gauges and I don't personally know any who made any effort to clean their blank tank either. Just dump, leave, and repeat as necessary. Why do people want their black tanks to be clean inside?

But then I'm considering the folk like I camped with back in the day who were never parked in one place more than a week. Maybe it's more important for someone who stays in a rig that doesn't move for months at a time.

[nomad_297]

DutchmenSport wrote:
The best thing you can do is leave a few gallons of water in the black tank and hit the road. The sloshing of the water will clean off the sensors. More is really not needed. The sensors very seldom, if ever truly work.

In time, you'll get "in-tune" with your camper and you'll know when it time to dump. You can always shine a flashlight down the toilet hole and see how full it is too when you "go".

But don't drop the flashlight!

Bruce

[DutchmenSport]

The best thing you can do is leave a few gallons of water in the black tank and hit the road. The sloshing of the water will clean off the sensors. More is really not needed. The sensors very seldom, if ever truly work.

In time, you'll get "in-tune" with your camper and you'll know when it time to dump. You can always shine a flashlight down the toilet hole and see how full it is too when you "go".

[edbehnke]

never ever had a gauage that worked!

figure if fulltiming for 2 people about 2 weeks. remember when you dump to have the tank fairly full to help the waste go out.

[ksg5000]

Ignore it, use a water flushing wand though the toilet opening, water/ice combo, or if your patient you can put septic tank cleaner in a wait a week or so. It's a common problem - usually associated with hanging toilet paper/crude on sensors.