Newbie question

**Hitsman3** · 07-07-2020, 12:50 PM

This is our first TT, so still learning things. Questions is we have (2) grey tanks, i understand we dump them separately, but as they fill up do they work together or independently? This last weekend our grey 1 was full & our grey 2 was 2/3 full. Not sure if one is just for kitchen and the other is just for bathroom or they work together? I asked a buddy we were camping with but he was unsure as his trailer is over 10 years old and only has 1 grey tank.

**livinthelife** · 07-07-2020, 01:34 PM

Originally Posted by Hitsman3

This is our first TT, so still learning things. Questions is we have (2) grey tanks, i understand we dump them separately, but as they fill up do they work together or independently? This last weekend our grey 1 was full & our grey 2 was 2/3 full. Not sure if one is just for kitchen and the other is just for bathroom or they work together? I asked a buddy we were camping with but he was unsure as his trailer is over 10 years old and only has 1 grey tank.

Each grey tank is independent. One is usually the bathroom, and the other the kitchen. So they typically "fill up" at different rates. There is a method to link them so that they equalize, but, only if the two tanks are on the same level. Sorry, someone else will need to fill you in on how that works.

You dump them either at the same time, or independently, depending on how full they are.

**boyscout** · 07-08-2020, 09:42 AM

Originally Posted by Hitsman3

This is our first TT, so still learning things. Questions is we have (2) grey tanks, i understand we dump them separately, but as they fill up do they work together or independently? This last weekend our grey 1 was full & our grey 2 was 2/3 full. Not sure if one is just for kitchen and the other is just for bathroom or they work together? I asked a buddy we were camping with but he was unsure as his trailer is over 10 years old and only has 1 grey tank.

As @livinthelife as said, except that I'd advise dumping them separately rather than at the same time.

The reasoning is that one wants to maximize the turbulence and flow out of each of the tanks in order to disturb and carry out as much as possible of the oils and solids that may be in the tank. Dumping both tanks at the same time means that twice as much sewage is trying to escape through the same 3" pipe, which will reduce flow velocity in both.

Here's a routine followed by some here.

1. Dump the black tank with the black flush running.

2. When the output is a clear trickle (the black flush running) close the black tank while leaving the black flush running. Do not leave the area to do something else because the black flush is re-filling your closed black tank. Overfilling it can expensively RUPTURE the tank. I set a six-minute alarm on my phone so I don't forget this important fact, which is usually long enough to put about 15 gallons of flush water into the black tank.

3. Dump the kitchen gray tank while the black tank is refilling.

4. Leaving the kitchen gray open, dump the black tank again with black flush still running. You will almost certainly see more black sewage coming out along with the last bits of whatever came out of the kitchen gray tank but didn't make it all the way to the outlet.

5. When the output is again reduced to a clear trickle, dump the bathroom gray tank while leaving kitchen and black tanks open and black flush still running.

6. When the output is again reduced to a clear trickle, turn off and immediately disconnect the black flush water supply, allowing the fresh water in the black flush system to run back out the supply inlet. (This is an important safety feature to prevent bacteria from developing at the flush supply inlet.)

7. Close all tanks.

8. Go inside the trailer and put about five gallons of fresh water (and some Dawn dish soap if desired, search for "GEO Method") into each of the tanks. This ensures that nothing solidifies on the bottom of the tanks before they are refilled with sewage.

I have sometimes repeated steps 2 and 4 as many as four times before seeing the black tank dump clean. To reduce odor and solids build-up in the tank, flush it multiple times like that when your time and patience allow it.

Hope this helps.

**livinthelife** · 07-08-2020, 11:03 AM

Originally Posted by boyscout

As @livinthelife as said, except that I'd advise dumping them separately rather than at the same time.

The reasoning is that one wants to maximize the turbulence and flow out of each of the tanks in order to disturb and carry out as much as possible of the oils and solids that may be in the tank. Dumping both tanks at the same time means that twice as much sewage is trying to escape through the same 3" pipe, which will reduce flow velocity in both.

...
Hope this helps.

Sorry, I understood "at same time" as in dumping both tanks during the same dump session, not as in opening both valves at the same time. As opposed to dumping one tank one day/time, and the other tank another day/time