When we purchased our used 2012 Montana 3750FL, DW and I took it out on a shakedown cruise. There were a couple of issues that were easily fixed, so no further problems there. But when I emptied the black tank, I noticed there was still fluid and some solids still in the bottom of the tank. I flushed the tank several times using the built in tank flusher. Weak flow by the way. Even after I stuck a hose down the toilet. I even filled it with a 5 gallon bucket to verify the capacity. There's always fluid and gunk left over. I can't seem to get everything out. You may find this gross, but I even taped my iPhone to a yard stick, turned on the video camera, and stuck it down the toilet to see what was down there. So after reviewing the tape, I noticed that the tank empties at the side, right below the toilet. And right in front of the hole, there seems to be a bulge in the tank. Right below the toilet where everything drops. It's about 1/4 inch below the level of the drain pipe. The rest of the tank drains just fine, but there's always this large puddle of nastiness left over.Just to be clear, my intent is to NOT leave the tank completely dry. I generally pour in a five gallon bucket with RV RidX and Calgon after I flush the tank. But I'd love to be able to get all the nastiness out before I do that.Is this an inherent problem with all black tanks, or is it just mine? How do I get rid of the bulge/puddle? Is this something I need to take to a dealer to fix, I can fix myself, or am I just up a puddle without a paddle and have to live with it? Thanks in advance for any help.

Frankly, you don't want it to empty completely. You always want some liquid in the tank. You should not get any bad smells. A bit of liquid in the bottom will help to keep the solids flowing when you drain the tank.

Sounds like maybe your black tank has a factory defect? Only fix I can think of is replacing it.My black tank (on a 21ft TT) can be rinsed completely, all solids cleaned out, if I take the time to do it.

You have a Poo pyramid. Most likely from using it with the valve open. Fill it to over half full, and let soak to soften and break up. Drive around awhile, curvy roads are best to slosh/agitate it around to break it up. Dump and repeat as needed. It may take several times to fully get it cleaned up. Filling it to about a 1/4-1/3, add a half of a small bottle of dawn to it, and dumping 20 pounds of ice in it, before driving it around will also help break it up. If it is pretty solid, a good soaking first will help greatly. When clean after dumping, put in at least 5 gallons of water with your treatment for best results. Never be stingy with the water when using either.

Sorry I am still stuck on the visual of sticking the iPhone 'down the toilet'!

It would be a PIA to do BUT - when you dump bring wood planks and place them on the opposite side of where your "indention" is - ride up on them - try cleaning your tank and use your on board rinser - see if that helps!

Black Tank Issues | Good Sam Community

paulcardoza
Explorer
May 08, 2015
I would suggest that you are freaking out over nothing.

Dump the tank, every few dumps, use the tank flush and NEVER stick your iPhone down there again.

Instead, spend more time enjoying your camping time.
Wishbone51
Explorer
May 08, 2015
At least you didn't sacrifice a perfectly good Android. :P

Completely disgusting, but totally clever. I tip my hat to you. :)
Old-Biscuit
Explorer III
May 08, 2015
Fill....dump....rinse......repeat

Don't look for problems or make RVng complicated.
DO you go Iphoneing down your home toilet?
rockhillmanor
Explorer
May 08, 2015
Posted By: paulcardoza I would suggest that you are freaking out over nothing.

Dump the tank, every few dumps, use the tank flush and NEVER stick your iPhone down there again.....

X2

And don't forget to wipe.........the iPhone that is! :B
RoadAbode
Explorer
May 08, 2015
rockhillmanor wrote:
Sorry I am still stuck on the visual of sticking the iPhone 'down the toilet'!

X3. I clean my black tank as best as can be, but no way am I sending my Samsung down to "take a look around!"
Wishbone51
Explorer
May 08, 2015
Would a GoPro fit down there? They are waterproof. :B
2oldman
Explorer II
May 08, 2015
How does a phone get enough light to make a video?
Wishbone51
Explorer
May 08, 2015
2oldman wrote:
How does a phone get enough light to make a video?

Most phones have built-in lights for the camera.
Dave_H_M
Explorer II
May 09, 2015
If that is a poo pyramid, search for poop pyramid and get the flex rinser from waliy world and blast that thing into smithereens. :W
BFL13
Explorer II
May 09, 2015
The OP did everything right. When the tank sprayers can't get it all ("stuff" happens?) stick a hose down the toilet and break up the stuff and get it all done as best you can.

The "visual" was his choice :)

Now a non-problem. Just keep using and dumping.

One thing you might not have that helps is a plastic see-through attachment to the sani-hose so you can see if you are really done dumping or if white paper clumps are still going by the viewing "window" It is actually quite entertaining, better than most television shows!

That way you can tell if your built in sprayer is finished doing any good and you can shut it all down, or if you need to keep at it.

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