Black tank deposits.

The friendliest place on the web for anyone with an RV or an interest in RVing!
If you have answers, please help by responding to the unanswered posts.

deank1

Well-known member
Joined
Jul 4, 2006
Posts
57
We are having a problem with what appears to be a coating/deposit flaking off the inside of the blank tank. We used Thetford dry additive for a couple of yrs and had odor problems, someone suggested we add dishwasher detergent to clean the tank. Not sure if that had anything to do with the problem but the scale comes off in large pieces at times. I was using a Sewer Solution unit but the pieces plug it up so now I am back to using the big blue hose. Anyone out there have a problem with hard scale in the black tank?
 

Steve CDN

Well-known member
Joined
Jan 31, 2005
Posts
2,388
Location
Canada/U.S.A
It sounds like your powder additive caked in the tank and perhaps your tank was stored empty of any water during periods of inactivity.

I would suggest connecting a hose to a hot water house faucet and feeding a hot pressure stream of hot water into your black tank through the toilet.

Drive around with the hot water for a while so there can be some agitation, then dump the tank.? You may have to repeat the process but that would be one way to dissolve the accumulation.

Many RV Forum members don't like holding tank additives, but I use a liquid additive that breaks down deposits and lubricates the valve gaskets.

If you are going to use an additive, use liquid, and always keep water in the black tank.

Of course one never leaves the black tank valve open while parked and connected to a sewer

:D
 

Terry A. Brewer

Well-known member
Joined
Mar 4, 2005
Posts
1,446
>> Anyone out there have a problem with hard scale in the black tank?<<


i had mine professionally pressure washed & had those same sheets of scale that I attribute to the hard waters in the west that accumulated on the sides over time.
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
Terry A. Brewer said:
>> Anyone out there have a problem with hard scale in the black tank?<<


i had mine professionally pressure washed & had those same sheets of scale that I attribute to the hard waters in the west that accumulated on the sides over time.

Could it possibly be dried TP?  The kind that is not safe for septic tank use.  Like Thetford?
 

Terry A. Brewer

Well-known member
Joined
Mar 4, 2005
Posts
1,446
Carl

>>Could it possibly be dried TP?? The kind that is not safe for septic tank use.? Like Thetford?<<

No I only used Scott's single ply. These were about the consistency of thin ice & about as brittle, they came off as he pressure washed the sides of the tank.

 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
73,979
Location
At our Silver Springs FL home
Scale is pretty normal on a black tank - it's a coating of crud that dries on whenever the tank is empty. It happens more to occasional Rvers than to fulltimers, since he fulltimer's tank is rarely empty & dry.
 

wesh

New member
Joined
Jul 17, 2006
Posts
2
I want to thank RV Forum and each who contributed to this topic.  I am new to this forum and appreciate what all of you are doing.

We have an ongoing problem of a terrible odor from our black tank that doesn't smell like feces or urine. It is a distinctive SOUR, foul smell that drives us out of our coach.  I wash it and wash it and wash it; then, after a day or two, the odor returns.

I got some good ideas from each of you and admire what you are doing so unselfishly.

Wes Hackbarth
Las Vegas, NV 

AKA wesh

[email protected]
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
Terry A. Brewer said:
Carl

>>Could it possibly be dried TP?? The kind that is not safe for septic tank use.? Like Thetford?<<

No I only used Scott's single ply. These were about the consistency of thin ice & about as brittle, they came off as he pressure washed the sides of the tank.

You know it might be potassium/sodium nitrate.  That was a common deposit in old fashioned cesspools and back in the old days it was used as a source of KNO3 for gunpowder.
 

Carl L

Moderator Emeritus
Joined
Mar 14, 2005
Posts
7,239
Location
west Los Angeles
wesh said:
We have an ongoing problem of a terrible odor from our black tank that doesn't smell like feces or urine. It is a distinctive SOUR, foul smell that drives us out of our coach.? I wash it and wash it and wash it; then, after a day or two, the odor returns.

[email protected]

Is the smell the rotten egg smell of hydrogen sulfide?
 

Gary RV_Wizard

Site Team
Joined
Feb 2, 2005
Posts
73,979
Location
At our Silver Springs FL home
Deank1,
Are you sure it's the black tank?  There is a microbe that sometimes thrives in water heaters of RVs that has a sour, sulphur odor and is sometimes mistaken for tank odor.  It is often most noticeable after running warm water in the sink. Has also been known to live in sink drains.  And of course gray tanks can easily get that odor from food wastes.  If your sink traps don't keep water in them, the graytank odor canback up into the room.

Assuming it is the black tank, do you get odor only when you flush or does it build up in the room even when the toilet is not used?    If the latter, what brand and model toilet is it?

Also, what have you tried to clean it out with so far?

 

wesh

New member
Joined
Jul 17, 2006
Posts
2
Being new to the Forum, I can't figure out how to reply the nice folks who are trying to help me.  I went to the help portion but it seems inadequate.  No,  I seem inadequate.  That's more accurate.


Wes Hackbarth AKA wesh

[email protected]
 

Ned

Moderator Emeritus
Joined
Feb 1, 2005
Posts
25,107
Location
USA
Wes,

For a public reply, do just what you did.  If you want to contact a staff (or any) member privately, you can use the IM icon under the member name.  If an envelope icon is there, you can use that to send an email.
 

Karl

Moderator Emeritus
Joined
Mar 3, 2005
Posts
5,154
Location
Elkhart Lake, WI for the summer. Work at Road Amer
Wes,

The odor could be because of a blocked vent tube on the roof. Tie a heavy bolt or something else to some fishing line and drop it thru the opening to check if that's the problem. Wasps and spiders will sometimes build nests inside openings like these.
 

Rex

Well-known member
Joined
Feb 15, 2006
Posts
253
Location
Alabama Gulf Coast
Well, I have had the same thing, and I also use the Sewer Solution.  I found that by using the Sewer Solution jet valve and turning it, I could clear the blockage.  I would close the black tank valve, clear the Sewer Solution, disconnect it and let the flakes fall out.  Then go back to normal dumping.  I would get the flacks about every 10 dumps. 

You might try filling the tank about 1/4 full, then put 1 - 2 bags of crushed ice down the toilet.  Then drive around about 30-minutes, and make lots of turns.  The ice will do a job on flake removal.  You will still get some flakes from time to time, but you can repeat this ice process and take care of it.  After you finish the 30-minute drive, you can dump using the slinky hose.  If you want to use the Sewer Solution instead, wait about 2-hours more so that all the ice has time to melt.

I hate the slinky hose, and have used only the Sewer Solution for 6-years.

Rex
 

Karl

Moderator Emeritus
Joined
Mar 3, 2005
Posts
5,154
Location
Elkhart Lake, WI for the summer. Work at Road Amer
You know it might be potassium/sodium nitrate.  That was a common deposit in old fashioned cesspools and back in the old days it was used as a source of KNO3 for gunpowder.
Gee Carl, if that's the problem he could just throw a handful or two of sulfur and charcoal down the toilet, and let it dry out. One match and POOF!  No more flakes ;D ;D ;D (also, no more MH)
 
Top Bottom