Another stinky black tank

johnp1959 · 07-18-2014, 10:01 PM

Ok, I am camping this weekend for the 5th time since buying a 2004 Sunseeker 3100 Motorhome. The bathroom has had a stink to it since the first trip so i decided to buy the Camco back flush valve with the pull valve on it to fill and flush my tanks. What i found was that the black tank actually became pressurized to the point that when I flushed the toilet while back flushing the black tank at 2/3 full or fuller the water in the toilet bowl would spray out of the toilet from the pressure in the tank. I am not sure how to check the vent pipe or even how it is hooked up, I have a black tank and a grey tank on the drivers side and a galley tank on the passenger side. On the roof there is one vent on each side. Any suggestions would be appreciated. The wife complains about the smell avery trip.

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wantahertzdonut · 07-26-2014, 06:04 PM

I assume you've already tried washing the tanks with the dish soap then driving to your destination.

I also assume you leave a few gallons of water in the black tank. Don't let it run dry or it will stink bad.

I've had better luck flushing the tanks with the cleaning wands that you stick in the toilet, spray for a while, and then close the black tank valve. It hoses everything out rather than relying on the flow of water to clean the tank like the backfill valves do.

For smell I pour in some cheap general purpose cleaner, as in the stuff that's $3 for a gallon. Usually bottom shelf Mr. Clean knockoffs at the grocery store since they're the cheapest. Little if any smell and you don't need to make a special trip to the RV store or walmart for the overpriced rv specific stuff.

When you return home, make sure to put a few gallons of water in after you've washed the tank.

hankpac · 07-26-2014, 06:19 PM

But you also asked how to be sure the vent pipe is going into the black tank. I suggest putting a "Fishing tape" down the pipe from the top, and see if it comes back out black. Of course WEAR GLOVES. And of course be careful with back splash etc.
That would tell you if the vent pipe is going into the tank.
Now, back to the smell.
First of all, the toilet needs an air seal: that is to say it mush have a inch or so of water in it so smells don't rise up past the rubber seal.
Secondly, while perfumed or anti-bacterial agents will help, it is important to realize that the black tank is supposed to work as a "digester" Solid human waste becomes a slurry when it sits in the tank. It won't do that nearly as well if you don't use enzymatic products intended for black water tanks.
For clean out, the important issue is to use plenty of water, and allow the tank to fill up to at least 3/4 before emptying. That flush takes all the waste out, helps dissolve solids, and generally works better. Never merely leave the black tank open when hooked up.
Some people try a lot of different things to clean out that tank, but remember what it is holding. Work with the process and you will be much happier.
That is if the vent pipe is actually hooked up.

wantahertzdonut · 07-26-2014, 06:28 PM

Quote:

Originally Posted by hankpac

Secondly, while perfumed or anti-bacterial agents will help, it is important to realize that the black tank is supposed to work as a "digester" Solid human waste becomes a slurry when it sits in the tank. It won't do that nearly as well if you don't use enzymatic products intended for black water tanks.

It's a holding tank, not a septic tank. If you have something digesting sewage then you're going to have a plume of methane on board, and nobody wants that!

dave961 · 07-27-2014, 06:57 AM

To resolve my stinky tank issue, I dumped half a bottle of dishwasher soap in the almost empty tank and all the ice cubes in my freezer's ice maker before driving to a campground. Hooked up at the campground, filled the tank and drained it over and over again till the water was clean. repeated this process on my next trip and the tank no longer smells.

Now I flush repeatedly when leaving a campground till the water is clear (clear plastic elbow), put 2-3 gallons back in tank with some sort of enzyme cleaner. The only remaining issue is that my black tank flush seems clogged. I have to get under there and follow it from one end to the other to find the issue, may not be in the tank.

bubbles · 07-27-2014, 07:51 AM

Quote:

Originally Posted by dave961

To resolve my stinky tank issue, I dumped half a bottle of dishwasher soap in the almost empty tank and all the ice cubes in my freezer's ice maker before driving to a campground. Hooked up at the campground, filled the tank and drained it over and over again till the water was clean. repeated this process on my next trip and the tank no longer smells.

Now I flush repeatedly when leaving a campground till the water is clear (clear plastic elbow), put 2-3 gallons back in tank with some sort of enzyme cleaner. The only remaining issue is that my black tank flush seems clogged. I have to get under there and follow it from one end to the other to find the issue, may not be in the tank.

Your first post did sound as though the black tank was not vented. have you verified the tank is vented? Just curious.

PhoneDude 8289 · 07-27-2014, 08:13 AM

After the tank is drained leave drain valve open and stick a water hose down the vent pipe and turn on the water. Check to see if the water from the hose is coming out of the drain, if it is then you vent pipe is hooked up. If the water from the hose backs up out of the vent then you have a clog or the vent could be pushed to the bottom of the tank. If water is coming out of the drain that test is over. If after a 1/4 tank or so it starts to build pressure again then the vent pipe may be pushed 1/2 way or more into the tank. When the contents of the tank reaches the vent pipe the pipe no longer vents and pressure will build. When you drain the tank does it drain quickly as it should or is it slow draining. A bad vent will cause it to drain slow.

wantahertzdonut · 07-27-2014, 12:35 PM

If the vent is pushed all the way into the tank like you say presley, what can be done to fix that?

If that is the case, it doesn't say much for the build quality at the factory.

OldCoot · 07-27-2014, 12:42 PM

Quote:

Originally Posted by wantahertzdonut

If the vent is pushed all the way into the tank like you say presley, what can be done to fix that?

If that is the case, it doesn't say much for the build quality at the factory.

Measure down thru the pipe to the bottom of the tank and then pull the pipe up about 6" and block it up. You can block it up by drilling a 1/4" dia hole completely thru the pipe and stick a ss bolt thru it and hold the bolt off the roof with plastic or alum. Caulk around the pipe.

johnp1959 · 07-28-2014, 06:47 PM

Thanks for all the great replies. Here is an update on what I have done so far. I noticed that when I flushed the toilet a small amount of water leaked out the front by the band clamp, it was a sealand ceramic bowl toilet. I decided to replace the whole toilet rather than replace seals in the old one just so I new that it was not a toilet issue. I also went up on the roof and put my ear to the vent pipe. When the toilet was flushed I could hear water running in the pipe and also an odor came out of the pipe. We went camping over this past weekend and there was no smell at all in the bathroom for the first time. I was not hooked up to a sewer this time and did not want to be that guy at the dump station, so I was not able to back flush the tank this time. Next time I get a chance I will try what presley01 suggests and put a hose in the vent pipe and see what happens. I am thinking the vent might be pushed down part way into the tank since it seems to get pressurized at 2/3 full. My only question to that is wouldn't the seal at the roof be broke if the pipe dropped down? Mine is not. And when I dump a full black tank it does seem to empty just as fast at the beginning as it does at the end. Thank you again very much.

JohnandPandra · 07-28-2014, 07:17 PM

We had black tank smells during hot temps right after we purchased our TT. I installed the Cyclone vent and NEVER had any more issues. Liked it so much I also installed one on the grey water tank and didn't have to put in the tablets that go into the drain anymore. Have to do what works and that vent works. I installed a Tornado Black Flush just to keep the tank clean, not for any smell issues. Good luck and many campfires to you and the family!

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