# Possible Holding Tank Mod.



## s'more (Jun 8, 2005)

OK now don't make me feel too bad for asking java script:add_smilie("shy")
shy.gif..... but why are there two holding tanks ???









I mean, when you dump them, doesn't the "stuff" end up in the same place ??? And if so, then why does the TT have two tanks to keep the icky grey water







away from the really, really icky black water





















What's the point ???

Where I'm going with all of this icky talk, is assuming that 2 holding tanks serve a purpose (and I'm sure they must), then after dumping the black water tank, would it be helpful if there was a way to dump the grey water into the black water tank, then re-drain the black water tank to help flush out any remaining sewer salmon or brown trout ???

Like this;
1. Drain black water tank.
2. Drain grey water tank into black water tank.
3. Drain black water tank again, thereby giving it a bit of a dirty rinse.









Thoughts ??? Opinions ???


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## HootBob (Apr 26, 2004)

O.K. why there are two different tanks not really sure
As for connecting the grey tank to the black tank to be able to use the grey to raise out the black is a thought. And why they didn't think of it








So the Mystery of life continues

Don


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## W4DRR (May 17, 2005)

Because, in a pinch, you can always dump the gray tank on the ground (at least in some places). Also, while camping without sewer hook-up, it is your gray tank that fills up the fastest, especially given the small capacity of the Outback tanks. Since it is only sink/shower water, it is not such a big deal to drain it off into a tote tank and haul to the dump station. Dumping a black tank this way is not desirable









Bob


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## bweiler (Sep 20, 2005)

good points. I always drain black 1st and then drain the grey to at least rinse out the drain lines. There are a lot of great threads on how to treat the black tank and rinsing with different flushing mechanisms. Everyone seems to have their own special way. Whatever works!


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## CamperAndy (Aug 26, 2004)

You can do this. I actually do it myself if I do not have time for a complete tank flush or have access to a water hose.

You will need a Flush King or similar external valve on the outlet.
First connect your outlet valve and open it. Open the black tank to drain it. Once it is mostly drained, close the outlet valve but leave the black valve open. Open the grey tank valve. Wait for the sounds of moving water to stop, this equalizes the tank levels. Close the gray tank valve. Open the outlet valve and a few more of the fish can make it down river. You can only do this may be twice before the grey tank is too low to help flush the black and you need to hold some grey in reserve to flush the hose out.


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## PDX_Doug (Nov 16, 2004)

The reason for keeping the gray and black tanks seperate is to keep the raw sewage - and everything associated with it - out of the loop as much as possible.

The plumbing in a TT is not the same as that in your house. Besides the lack of vertical space for proper traps (especially in the tub), the stored water is subject to a lot of forces trying to slosh it around when in motion. You really don't want the fumes and bacteria coming up through your sink and/or tub drains!

As far as cross connecting the tanks is concerned, this presents a similar path for the bad stuff to get into the system. I suppose you could install a good gate valve between the two tanks, and only open it when flushing the black tank... but, frankly, a QuickieFlush would be a lot easier!









Happy Trails,
Doug


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## Humpty (Apr 20, 2005)

Agree - Black tank separate to keep it isolated as much as possible.

We accumulate a LOT of grey water when we camp. Sensors are never close. We know the tank is full when water backs up into the shower.

Only one holding tank would be a problem.









I saw a mod on â€˜anotherâ€™ sit where a guy added a pump so he move grey water to the black tank to add capacity for holding grey water. He routed the line to the Black tank vent (above the full level point) to keep black water back flow into the grey tank.


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## h2oman (Nov 17, 2005)

Doug is quite correct on this matter. You would not want the black tank backing up on you while in the shower or anywhere else for that matter. Therefore, it is plumbed on a completely seperate system.


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## Thor (Apr 7, 2004)

I am also with PDX on this one. Keep black and grey separate. Your grey water will fill up the quickest and when it is full your shower will back-up. Now imagine if it had black water with it







.

Another good point is that your porta tote tanks are much better when only grey water is used. Some areas will allow you to dump grey only.

As for keeping your blank tank free and fresh - quickie flush device is a most mod.

As for dumping

I do the following

1. attach hose to quickie flush and turn on for a few minutes
2. open black water until the flow is very little
3. Close the valve and let the quickie flush fill the tank
4. Open valve and drain again
5. Turn off quickie flush
6. close black and open grey

I repeat the cleaning process based on if there are people behind me or it is the last dump of the season.

Thor


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## gone campin (Jan 29, 2006)

I'm glad that they are not the same tank.

The first time we went out in our brand new TT that we had just bought (2 years ago). I went into the bathroom to find my dirty clothes floating in the tub. Oh my did I flip out. I had no clue what all that water was doing in the tub with all my dirty clothes. That only happened ONE TIME! Boy have I learned alot in two years. I make sure I don't leave the spigot running and I check the tanks, I dump when they register 1/2 full now.


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