How full is full? (black tank)

[Boubou]

Been parked for 9 days at a CG with no sewer on site. We've been careful to go to the toilets on the CG most if the times except nights and early morning. Of course, the sensor showed 3/4 full after two days so we knew not to trust it too much from there but I think the waste have caught up to the sensor by now.
Question is: once the sensor shows full, how much room is there still? ( kinda like how far can we drive on Empty).
We still have 5 days before going home and would rather not have to go dump until ready to go.
Also, what happens if we keep using when the sensors mark full if we can't see anything in the tank through the toilet hole?

[Grumpy]

It all depends on how big your tank is, if you can't see any waste when you look your OK. We have gone 2 weeks already and we only use the camper and it has a 51 gal tank. .

[norty1]

If you see the splash when you flush, it is full!

[Boubou]

37 gallons. No splash yet and we see nothing either. We probably will be able to wait until monday to flush then.
Thanks for the help

[newbold1]

Once you can see the waste in mine it is FULL and it is pretty nasty. Have to empty right away at that point as the odor is foul. I notice mine will go from zero odor to horrible the moment it is truly full. First time I had that happen I've since made a point not to let it get there ever again if I can help it. Lol 😄

[bigbird]

Our tank is 28 gal and the black tank would probably go for at least 7 days for the two of us and we don't use the campground toilets. Our trips are usually 5 nights and when time to dump I can add at least seven more gallons to completely fill it. Now on the other hand our 30 gal grey tank is full in 2 1/2 days (shower at campground) but we have at blue tote for that which is used once in the middle of our 5 day trip.

[Threebutchers]

Too full!!!!!

[clutch]

Just take a flash light and shine it down the hole. You can see how full it is. 37 gallons is a LOT of poo and takes a while to collect.

[Boubou]

On the road again...
We made it a full 14 nights on
37 gallons black tank. The sensors still showed 3/4 full and looking in with a flashlight, I could see there was still about 2 inches to the top of the tank. We used the parks toilets during the day but morning/ evenings and nights we used ours. Our trick which is a little gross (but we didn't want to hook up a d dump) was to throw the toilet paper into the trash and only flush when toilet was full and allow only a little fresh water back into the bowl for the seal. (Flush each time for the brown stuff of course).
Dumping this morning was all concentrate!!!

[Threebutchers]

Originally Posted by Boubou

We made it a full 14 nights on 37 gallons black tank.

:excited:

Originally Posted by Boubou

The sensors still showed 3/4 full and looking in with a flashlight, I could see there was still about 2 inches to the top of the tank.

THAT was brave!!!...

Originally Posted by Boubou

We used the parks toilets during the day but morning/ evenings and nights we used ours. Our trick which is a little gross (but we didn't want to hook up a d dump) was to throw the toilet paper into the trash and only flush when toilet was full and allow only a little fresh water back into the bowl for the seal. (Flush each time for the brown stuff of course)!

Exactly what we do!!!.... if it's yellow, it's mellow....if it's brown, send it down....[ATTACH][/ATTACH]

Welcome to the JOF baggers club! We are making a modified sticker you'll be able to order online....:wink:

[rosedan]

30 Gallons of POOH what kind of animal can do that kind of damage in a week??? I don't think they see that kind of volume at the Zoo's Rhino cage.

[Kave&Lucky]

Originally Posted by rosedan

30 Gallons of POOH what kind of animal can do that kind of damage in a week??? I don't think they see that kind of volume at the Zoo's Rhino cage.

WELCOME TO THE JUNGLE!!!

[EnricoG]

When you have time, you can do a little experiment to determine what the full light on the sensor actually means. Once you have dumped your black tank, start filling your tank by pouring water down the toilet using a 1 gallon jug. Check how many gallons have gone in when the sensor shows 1/3, 2/3 and 3/3 full. I tried this and have it written down in the rv. I think mine was at 22 gallons when the sensor panel showed full - the tank is 32.5 gallons!

[Gibby3275]

When the black tank is getting too full, it's a good time to go on that diet you know you should be on.
Eat less, poop less...............as the saying (that I just made up) goes.

[samiam95124]

Originally Posted by EnricoG

When you have time, you can do a little experiment to determine what the full light on the sensor actually means. Once you have dumped your black tank, start filling your tank by pouring water down the toilet using a 1 gallon jug. Check how many gallons have gone in when the sensor shows 1/3, 2/3 and 3/3 full. I tried this and have it written down in the rv. I think mine was at 22 gallons when the sensor panel showed full - the tank is 32.5 gallons!

I don't believe it works as you are thinking. The lights indicate each 1/3 of the tank is crossed (on mine it is 1/4s). Thus, that last light
indicates you are STARTING the last 1/3 of the capacity, by definition, because you filled it until you just saw it light up. Thus, 2 3rds of 32.5 is 21.6 gal, which actually makes your gauge surprisingly accurate.

[glsimms]

Originally Posted by samiam95124

I don't believe it works as you are thinking. The lights indicate each 1/3 of the tank is crossed (on mine it is 1/4s). Thus, that last light
indicates you are STARTING the last 1/3 of the capacity, by definition, because you filled it until you just saw it light up. Thus, 2 3rds of 32.5 is 21.6 gal, which actually makes your gauge surprisingly accurate.

Good to know!!!

[EnricoG]

Originally Posted by samiam95124

I don't believe it works as you are thinking. The lights indicate each 1/3 of the tank is crossed (on mine it is 1/4s). Thus, that last light
indicates you are STARTING the last 1/3 of the capacity, by definition, because you filled it until you just saw it light up. Thus, 2 3rds of 32.5 is 21.6 gal, which actually makes your gauge surprisingly accurate.

I think we're thinking the same thing, which is exactly why I did the measurement. My panel is marked E, 1/3, 2/3, F. After measuring I know that E means I have 0 - 6 gal, 1/3 means I have somewhere between 6 gal and 13 gal, 2/3 means I have between 13 gal and 22 gal. F means I have 22+ gal. The volume delta for each LED is not the same - presumably because the sensors are fitted without taking into account the shape of the tanks.

[samiam95124]

Originally Posted by EnricoG

I think we're thinking the same thing, which is exactly why I did the measurement. My panel is marked E, 1/3, 2/3, F. After measuring I know that E means I have 0 - 6 gal, 1/3 means I have somewhere between 6 gal and 13 gal, 2/3 means I have between 13 gal and 22 gal. F means I have 22+ gal. The volume delta for each LED is not the same - presumably because the sensors are fitted without taking into account the shape of the tanks.

I have actually wondered if these are all capacitive gauges, which most of the new offerings appear to be. This is a method by which a metal disk is placed external to the tank, and it is measuring the capacitience of the water through the wall of the tank. The reason it matters is that the capacitive gauge is going to be calibrated. There is no real exact sensing of the level, it is going to be sensing the level according to when the capacitence of the sensor reaches a set level.

If that is true, it seems possible you might be able to calibrate the thing.

[EnricoG]

The expensive ones may be, but the cheap sensors on most rigs are just probes that make electrical contact via the "liquid". That is why their readings are not very reliable - if toilet paper or other nasties get stuck on the probes they can indicate a non empty tank even if it is empty. Using a black tank flush helps prevent this to some extent.

[samiam95124]

Originally Posted by EnricoG

The expensive ones may be, but the cheap sensors on most rigs are just probes that make electrical contact via the "liquid". That is why their readings are not very reliable - if toilet paper or other nasties get stuck on the probes they can indicate a non empty tank even if it is empty. Using a black tank flush helps prevent this to some extent.

I got my tank flusher to work (quickie flush). It seemed to be flushing an endless amount of crud out. The camper has only been used twice! I think it is pushing a lot of excess silicone sealant and other manufacturing swarf out.