# Noob Blackwater Tank Question



## byron (Jul 31, 2007)

Mr Noob again:

While I'm waiting for my OB trailer and trying to get as smart as possible, I'm wondering about something.

I see all the issues and suggestions with blackwater tank problems.

Do you avoid all these by using full hookups only? I assume the toilet water goes straight to the campsite hookup in this case thereby avoiding going thru a tank.

Or does it go thru the tank first, then to the sewer hookup?

Thanks.

Byron


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## TheMillers (Aug 8, 2005)

It always goes through the tank. I keep the both valves closed even in full hookups. If you leave them open, the liquid will leave the tank, but the solids might stay. It drains better when the tanks are full. The advantage to full hookups is that you can fill and drain your tank again (or use a quicky flush, tornado, etc) to really make sure it's cleaned out.

Bruce


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## mswalt (Sep 14, 2004)

I use full hookups every time I can get them--no need to worry about conserving water in your gray tanks then. Leave the black tank closed and dump when full. Full tanks help evacuate the tank.

You can, howver, leave your gray tank open. I usually only leave my galley gray tank open when staying for more than a weekend. I drain the bathroom gray tank when necessary. I also use whatever is left in the gray tanks to clean out the pipes after draining my blank tank.

Mark


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## HTQM (May 31, 2006)

Byron,

Bruce hit it on the nose, if ya want to get into the weeds of why... read on;

The OB has half of your house septic if you have a septic tank and not city sewer. When you flush, the "stuff" goes thru the angle piping down 
into the holding tank. There, solids settle at the bottom and fluids disperse thru the drain field (fingers). Bacteria (pooh bugs) eat at the solids and send them up to the fingers, as long as they (bugs) survive the endless amount of bleach and other cleaners most of us put into the system. The first part of that happens in the OB, "stuff" goes into the tank and the solids lay on the bottom. If the tank valve is left open the fluids will head on down the sewer hose but the solids stay in the tank. Keeping the valve closed and letting the tank build up gives you the "rush" of fluids to carry to solids out when you open the valve. Follow that up with a Tornado or Quickie flush and your sure to get all of the solids out and maintain your tank in it's best condition.

Hope this helps
Dave


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## byron (Jul 31, 2007)

Thanks, it makes much more sense now.

Byron


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## TheMillers (Aug 8, 2005)

You mean you have 2 gray tanks? Wow I didn't know they did that.

Learn something new everyday...

Bruce



mswalt said:


> You can, howver, leave your gray tank open. I usually only leave my galley gray tank open when staying for more than a weekend. I drain the bathroom gray tank when necessary. I also use whatever is left in the gray tanks to clean out the pipes after draining my blank tank.
> 
> Mark


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## Oregon_Camper (Sep 13, 2004)

On Outbacks with only 1 grey tank, I'd recommend leaving it closed until

1) you have to empty

2) you're ready to empty the black tank...then follow with Grey tank. This give you a lot of water to clean out the shared pipe.


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