Level Gauge Black Water Tank...

Van Living Forum

Help Support Van Living Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Cy_5th

Well-known member
Joined
Jan 30, 2024
Messages
85
Reaction score
50
Location
Bay Area, California
Where would plumbing be under the "life on the road" section of this forum? Didn't see one. So maybe i can ask here. My black water level gauge is always off. I didn't really start using the inlet flush connection or spray hose into the toilet until probably two months of use.

I would empty the tank so it reads 0% on the screens I use it probably thrice it would already bump up to 33% or 67%. Sometimes It go back down to 33%. I emptied it on Sat. Granted where I am parked now is not level, not too far off from level. But now it reads 100%. I have a 12.5 gal tank.

So because i wasn't flushing the tank until now, those missed times, probably caused to sediment/crust to develop near the level gauge. Now its harder to flush the crust off?

In your guys gals experience, in a 12.5 gal tank. Its really depends on how much I go, that's me to know. But in your experience how long does it take to fill a 12.5 gal? I definitely know mine is not full just because it shows 100%. I can't really judge based on that reading. Its got to be based on how many times a go a day. And when my next trip to the dump site will be. Right now i go to the dump site, once a week. When i drive outta my location now. I will probably go back to 67%.

How do you guys deal with this?
 
It depends on what type of sensor your tank has. None work well or for long in my experience. Take a flashlight with the water pump off and open the flush valve and look at the level of the water in the tank. It is hard to judge the depth but eventually you get good at guessing. 12,5 gallons isn’t a very large tank so around 100 lbs could be easily carried in tote tank in the back of a vehicle. Using a cheap macerater pump would make it to where you wouldn’t have to lift anything.

Trick to clean the tank are first dump some dawn dish detergent and a bag or two of crushed ice in the tank after mostly filling it and drive a few hours over rough twisty roads then dump. Second they sell a spray wand that you can hook to a garden hose that you can put down the flush valve of the toilet to clean the inside of the tank. Non of these are sure to work as the sensors are junk in my opinion. They do make an external sensor you can install but again not sure how well they will work. With all the chemicals and material that goes into the black tank it doesn’t surprise me the sensor doesn’t work. We don’t put anything down the toilet that doesn’t come out of our body so toilet paper goes into a separate air tight container and into the trash. Guess what after doing all the above our sensor still intermittently does not work so I just look down the toilet into the tank. I guess you could use a stick and mark the it in gallon increments right after you dump it adding a gallon at a time but then you would have to clean and store the stick! Lol!!! We usually guess by figuring how much of the capacity of our fresh water tank we have left compared with what is in the gray water tank then the rest must be in the black tank plus a little over 1/2 again deposits. We usually fill the gray water tank twice as often as the black water tank. We have a 50 gallon fresh water tank, a 35 gallon gray water tank and a 25 gallon black tank. Hope this helps you and remember “results may vary” Lol!!!
 
We usually guess by figuring how much of the capacity of our fresh water tank we have left compared with what is in the gray water tank then the rest must be in the black tank plus a little over 1/2 again deposits. We usually fill the gray water tank twice as often as the black water tank. We have a 50 gallon fresh water tank, a 35 gallon gray water tank and a 25 gallon black tank. Hope this helps you and remember “results may vary” Lol!!!

My fresh water tank is 24 gal. Basically half of the Black. Freshwater goes down the black more that the grey. Ill add +/-5% that it goes into Gray. I take showers and use the sink more at my work facilities than the RV. And the level gauge in Freshwater is accurate. If it shows 75% left plus the 5% in gray. I would have filled 20% of the 12.5 gal tank. So the level should be around 20% fill.

Does that sound right?
 
Just off your use of the fresh water tank of 25% (6 gallons) and considering most of it went into your black tank plus your deposits (I’m assuming a gallon of feces and urine per 2 gallons of fresh water, really depends on how much water you flush and how much you as an individual deposit, which may vary) most likely there is somewhere between 4 to 6 gallons in your black tank or somewhere between 30% to 50% full. Again just a guess. You only can know for sure it’s level when it is full! The more water you run thru it the better. They do make a back flush attachment that goes between your gate valve and your dump hose using their attachment lugs which is handy at dump stations if they have a flushing water hose. By the way never fill your fresh water tank with the flush hose or use the fresh water hose to flush your black tank.
 
Just off your use of the fresh water tank of 25% (6 gallons) and considering most of it went into your black tank plus your deposits (I’m assuming a gallon of feces and urine per 2 gallons of fresh water, really depends on how much water you flush and how much you as an individual deposit, which may vary) most likely there is somewhere between 4 to 6 gallons in your black tank or somewhere between 30% to 50% full. Again just a guess. You only can know for sure it’s level when it is full! The more water you run thru it the better. They do make a back flush attachment that goes between your gate valve and your dump hose using their attachment lugs which is handy at dump stations if they have a flushing water hose. By the way never fill your fresh water tank with the flush hose or use the fresh water hose to flush your black tank.

I was about to edit my response earlier. So since my tank is half the freshwater tank size. Almost like your guess. Then its 40% full, my Black water.

Yes never use fresh water hose to flush the flush inlet connection or putting it through the toilet flush valve and into the black. LOL.

Ill probably buy that back flush attachments that goes in between my stinky slinky and the outlet of the black tank. Ill try that.
 
Good luck! Like I said we mainly through experience can usually guess when it will be full simply by the number of days since the last dump and usually guess too soon just to be safe! My tank has a small air space between the down pipe and the fluid. When it disappears I figure I’m a couple flushes away from having to dump a full tank.
 
Top