I can’t be the only one with a poorly designed black tank.

[PsnRebel]

Let me preface, this is not my first rv (it is my 1st Class A pusher) and we have 30+ years experience mostly boon docking, but do spend time in campgrounds also.

With that said, two years ago we retired and bought a used 2005 Mandalay Presidio. From the very first trip, at a campground with full hook ups, we were lucky enough to be introduced to a poop pyramid, that literally “exploded” when opening flushing the toilet. Getting black waste everywhere. Wonderful.

I always leave water in the bottom of the tank after flushing to assist in breakdown etc. When traveling (and occasionally when parked) there’s always an odor.

Traveling down the highway, the poop pyramid has been known to resurface. Every time this occurs i dump the tank as soon as possible, but it doesn’t correct my issue easily and immediately.

I now know what the issue is, this is where i need help. The main, large portion of black tank is not directly under the toilet. The inlet from the toilet is at the far right end of tank. This area of the tank might be 10” tall, in theory the solids are supposed to travel along an ever so slight grade, about 12” towards the larger portion of the tank where they are supposed to fall into the a much larger holding area. This is where the sensors are and main capacity of the tank is. The liquids of course run off this “shelf” with no problem. Leaving behind the paper and solids to slowly accumulate. Filling the bowl full of water before flushing only may delay the inevitable, but it eventually rears its ugly head.

When dumping the tank the only way to clear this area of the tank is to fill the tank with water to near capacity. There is a factory installed sani flush that is on the top of the tank, but not really anywhere near where the pyramid begins to form.

I don’t know how to solve this. I thought i could add another black tank flush where the pyramid forms, which may work, kinda when on city water. I don’t believe the onboard pump will have enough pressure to be effective if i plumb in it a way it could use it when not connected to city water.

So frustrated. Any ideas? Sorry i cannot get a good picture of my tank setup to give a better idea. Picture an upside down “L”, or an “L” shape where the long vertical line lays horizontal and the smaller horizontal line is now vertical.

Thanks in advance.

[PsnRebel]

dhull wrote:
Here's what we do to get around developing the dreaded ^ at the bottom of the chute in our TC. Having experienced it several times, once had to take a stick to it and once was able to shake the camper and it went on down.
Take a dish tub about 12x15x6 and fill it with water then pour it down the throat of the commode. Empty the tub as fast as you can. The volume of water hitting the solids moves it along. We do this every 2 days. Simply flushing extra toilet water down doesn't work nor does pouring it out of a gallon jug.

Thanks for all the suggestions.

This may be a solution.

I did a quick search on amazon and found there’s an “rv plunger.” Basically a stick with a rigid propeller type thing on the end to help move things along. Found it cheaper directly from the mfg. just received it yesterday. So I’ll give that a whirl. Literally.

I may still install a “tornado” type device near where the pyramid is forming. That will definitely help when having city water pressure. I was really hoping a suggestion would appear with a direct stream type black tank flush, that would give some “significant” pressure when hooked up to the rigs water line (to help solve the boondocking issue).

I replaced the faucet valves with the shower style hose end with two washing machine ball valves and connected a washing machine mixer hose, basically a “y” styled hose. I connected a short garden hose (2’) with a black tank flush (camco?) fitting to see what kind of result id get. Not real happy with the pressure or water stream it produced. I didnt install it for the test, just “bench” tested it into the grass.

Hitting the highway in a week, hopefully the “rv plunger” will assist in breaking down the pyramid and get things moving.

I think ill check the vent pipe if i have time before leaving, in order to rule that out as being an issue.

[dhull]

Here's what we do to get around developing the dreaded ^ at the bottom of the chute in our TC. Having experienced it several times, once had to take a stick to it and once was able to shake the camper and it went on down.
Take a dish tub about 12x15x6 and fill it with water then pour it down the throat of the commode. Empty the tub as fast as you can. The volume of water hitting the solids moves it along. We do this every 2 days. Simply flushing extra toilet water down doesn't work nor does pouring it out of a gallon jug.

[Ro_n_Joe]

Try using Unique RV Digest It which should dissolve the pyramids.

[enblethen]

It is difficult to determine where an odor is coming from. Grey tanks can smell as bad as black tanks.

[SJ-Chris]

One other thing that could be helpful...

Maybe if every time before you do a #2 in the toilet you first do a quick 3 second flush to send water down into your black tank and therefore onto the shelf. Then, maybe when you flush your business shortly afterwards it will drop down into the main part of your waste tank because maybe that shelf will already be wet and a little slipperier. Just a thought.

-Chris

[SJ-Chris]

Something that could help... If possible, install a flush (or Tornado flush) such that it runs along that shelf blasting everything away. Or if that's not possible, a Tornado flush that is pointed right towards the shelf to hopefully do some blasting of that shelf area. This would be useful only when you dump, but at least it gets "the shelf" clean/empty (hopefully) each time you dump so that you are starting from scratch rather than having it build up.

Here is a link to an easy, and inexpensive, install:
https://www.rv.net/forum/index.cfm/fuseaction/thread/tid/30315748.cfm

Note: This is different than simply "filling" your black waste tank (with perhaps your built in flush connection) and doing another flush. The Tornado flush actually sprays the water in the direction of your choosing (in this case, along the shelf or at the shelf). If nothing else, it also takes the place of having to stick "the wand" down the toilet (...which requires running a hose into your RV and playing around with the wand in the toilet inside the RV, and then having to carefully get it all back out of the RV which is all very painful).

Good luck!
Chris

[dougrainer]

enblethen wrote:
Air gap
If you fighting an odor problem, locate air gaps and replace them.

Air gaps are Gray tank problems. That is why he needs to do the procedures I outlined earlier. Doug

[enblethen]

Air gap
If you fighting an odor problem, locate air gaps and replace them.

[sssooo]

The odor could be coming from a washing Mach
if you don’t use it at all.
The piramid when you flush the toilet run a lot of water and when you think it’s enough run a little more that is what I do and it works for me!

[valhalla360]

Something just doesn't sound right. If what you describe is true, there really is no solution. A shelf well above the bottom of the main tank will always collect solids.

You can get wands that you hook to a garden hose and shove it down the toilet but to keep up with it, you are going to need to do it every 2nd or 3rd dump.

Odor is a different question that is unlikely to be related:
- Check that the roof vent is clear
- Check that the toilet seals are fully closing.
- Check that the seal between the toilet and floor is in good condition and in the proper location.

[PsnRebel]

Campforever wrote:
Fill black tank from inside the camper i.e., use a hose and stick in in the toilet close the toilet on the hose and start filling. On mine, with a 40 gallon tank I run it 11 minutes then drain.

I do this for about 4 to five cycles or until the water is running clear.

When filling from the toilet you should clear out the shelf.

Truely not a aftermarket design to benefit the buyer.

That is why we adapt, improvise, apply.....

Pretty much the exact procedure i do once the pyramid is formed and i have the “luxury” of being hooked up to a city water connection, or when we have to find a dump station somewhere along our travel route (usually bt CA or GA). Luckily Love’s truck stops typically have a dump to access.

I probably use 150-200 gallons of water to dump the tank properly. Similar to you it’s about 9-11 minutes between pulling the dump valve. So 4 x 10 minutes is an easy 40 minutes of baby sitting the hose and tank alone.

I was hoping my bathroom sink in the toilet “closet” was hooked to the black tank because we rarely use that sink. So id use it more if it was, hoping that would help, but its not.

[dougrainer]

Regardless of any accumulated deposits or a Poop Pyramid, you should NEVER get an odor stopped or in transit.
1. Use Pine sol. Fill and flush the tank 3 or more times. Then leave empty, no chemicals. Put about a pint of pine sol in the tank thru the toilet. Kame sure the toilet bowl DOES hold that little water(1 cup or so). Drive the RV. See if you get Pine sol smell. IF NOT, then your Gray tank is the cause of your odor. IF it does smell of Pine sol, then you need to pull the toilet and check its mount on the down pipe to the black tank. Verify the toilet flange seal is GOOD(I doubt it after all these years). Regardless, you now replace the flange seal. Get this flushing tool and use it to help clean out that ridge in your tank.

https://www.amazon.com/Camco-Straight-Valve-Creates-Dislodges-21013/dp/B07ZPJTKMH/ref=asc_df_B07ZPJT...

[pbitschura]

Maybe if you dumped some Galgon into your tank every time you dump, the black tank sidewalls will be too slippery for solids to stick. Maybe not the same but our recently sold 88 C had all tank gauges still working. We never had any build up. Good luck.

[Campforever]

Fill black tank from inside the camper i.e., use a hose and stick in in the toilet close the toilet on the hose and start filling. On mine, with a 40 gallon tank I run it 11 minutes then drain.

I do this for about 4 to five cycles or until the water is running clear.

When filling from the toilet you should clear out the shelf.

Truely not a aftermarket design to benefit the buyer.

That is why we adapt, improvise, apply.....