Black water tank - temporary storage

[mbCik]

I'm seeing in the forums a lot of different ways to keep the black tank when not in use.

Some people leave a few gallons of water in it, some do not. Others add soap.

My TT is parked next to my house and I'm taking it out camping about one weekend per month. I'm using the Geo method to dump the tank, but havent settled on a good method yet to store the tank for the couple of weeks per month.

I'm figuring, in my non-expert opinion, that leaving water in the black tank for several weeks is worse than leaving it empty. Seems like if there is water, there is lots of opportunity for things to get worse.

What has been your experience? Are both methods (empty or a few gallons of water) working well for folks?

P.S. My black tank only services the toilet. The shower and sinks all drain to the grey tank.

Thanks!

[kandl]

The only thing that stays in ours over the winter is that little bit of antifreeze and water that comes from winterizing the p-traps. Overfill the p-traps with antifreeze, that way you know some gets down to the gate valves with the residual water.

[banda]

What I see most often is the recommendation to leave a gallon or two of water and tank chemicals during storage.

[kandl]

Originally Posted by banda

What I see most often is the recommendation to leave a gallon or two of water and tank chemicals during storage.

That's gonna destroy the black tank outlet and gate valve during the -40 cold snap.

[mbCik]

Sorry, I should have mentioned that there is no issue with freezing where I live.

[kandl]

Originally Posted by mbCik

Sorry, I should have mentioned that there is no issue with freezing where I live.

No worries - relocation to the Wet Coast is on our bucket list. Getting weary of the two months of lousy dog sledding lifestyle.

[Witch Doctor]

You should always leave something in the tank winter or summer. You do not want your seals to get hard. In the winter a little anti, during the summer water and chemicals if that what you use, IMO you will have more problems if you do not keep some liquid in the bottom.

[jgahlhoff]

X2

[banda]

Originally Posted by kandl

That's gonna destroy the black tank outlet and gate valve during the -40 cold snap.

We don't have that problem in Texas!

[DickiedooFlagman]

Originally Posted by gljurczyk

You should always leave something in the tank winter or summer. You do not want your seals to get hard. In the winter a little anti, during the summer water and chemicals if that what you use, IMO you will have more problems if you do not keep some liquid in the bottom.

Without threat of freezing, leave some water and the normal potty chemicals in the tank. A dry tank will allow any remaining crud to dry out and cause future problems when trying to drain at a dump station.

[Wolverine]

I second the notion of never leaving the tank completely empty.

[tomrob1161]

After empting the black tan, I ad 2 toilet fulls of water plus an enzyme / bacteria type chemical like Kronen. Kronen doesn't have the strong formaldehyde smell and it helps keep the probes and tank clean and also lubes the seals.

[Reason201]

During camping season, leave a couple gallons of water in tank with a dose of tank chemicals. That will keep it from stinking. For last dump of season, I give it an extra good wash out and then leave the valves open when I winterize to get excess water out. Last step is to close the valves and winterize the traps with a bit extra so I know there is a little antifreeze in the tank just for safety against the valves. I have also heard to leave the tank valves open and put a piece of fine mesh screen over the dump outlet to both dry the tank and keep pests out of it.

[j free]

If you do a complete flush every time you are done with it the unit you should be ok. You will always leave a small amount of water in the tank because it is almost imposable to remove all of it. This would be enough water to keep seals moist. The chemicals are not needed while storing they will only last a limited time period and then do no good. They are primarily for deodorizing and breakdown of raw sewage and do no good by alone. Also some of them state not to do this practice.

[tomrob1161]

In the past, as reason201 said, I left my tanks open with a piece of plastic window screen over the open pipe to keep insects out. However, I was afraid the seals would dry out so, I started closing the valves again, with the little bit of RV antifreeze that was there from winterizing the system. However, when I read my owners manual on my 2013 Rockwood Signature Ultra Lite, 8315 BSS, it recommended adding a gallon of RV Antifreeze to each holding tank. Although our winters are real bad in Alabama, I felt this was a good recommendation to follow. I've got 3 holding tanks, so it takes an extra 3 gallons of RV antifreeze, but if you catch it on sale, the cost is minimal.

[markb5900]

I have had three motor homes, a pop up, a pull behind TT and a 5th wheel.
During the camping "season". I drain my tank when I get home at the local city park that has a dump station and that is it.
There is always a small amount left in the tank as stated above.
Since 1987 I have NEVER had a problem with seals drying out doing this method and never added chemicals while it was sitting in the drive way.
Now as a note, we do take it out at least twice a month so it doesn't sit long in the summer.
When I winterize, I do a REALLY REALLY REALLY good flush on it to make sure it is clean before putting it away for the winter.

[pmsherman]

A friend drained the black tank then left it dry while not using the trailer for a few months. The remaining gunk in the tank settled at/near the valve then hardened, totally blocking the drain. This was, of course, discovered when the black tank was almost full and couldn't be dumped.

An RV tech came out and was able to flush out the drain from the drain hose end, using a 6' long wand. I wasn't there when the clog came loose but I imaging that it was a sh***y experience. I'm glad it was the tech and not my friend doing this.

Moral - always keep liquid in the tanks. Use water in the summer and antifreeze in the winter.

Phil

[Jim34RL]

When we bought our first 5er way back when; I was taught by a very small dealer on what to do. The dealer provided 5 hours of instructions plus driving lessons. This included backing up the 5er since this was our first unit.

In the instructions for dumping the black tank and all the other tanks, was to leave them dry with no water in them when in storage. His reasoning was the water will evaporate over time and you where just wasting the water. He also stated that this will also lead to odors in the camper from the tanks as the water evaporates. He did state to flush them good and use the black tank flush port along with dumping several buckets of water down the toilet when flushing the system as you break camp. The tanks will be cleaned and debris will not pile up in the tanks.

I have done this ever since we purchase our first fiver and have had no issues with the tanks or the tank gage lights as they stay clean.

[ActionJackson]

I'm with j free and markb9500. I just drain the tank and rinse the tank by filling the bowl a coupe of times and flushing the toilet ( or however you prefer), let the sewer hose run until it's not dripping and then shut the gate valve. Never had a problem. No chemicals used. Non-freezing climate, I should note.

[mbCik]

Its great having so much feedback on this topic, thank you everyone! It sounds like I could probably go either way and be safe...The most important thing being that I thoroughly clean out the blank tank after use.