connecting grey tanks to get more capacity for the shower

[Lexx]

We're looking at the Grand Design Momentum 328m which has two separate 52 gallon grey tanks, one for the shower and another for the sink. It has 160 gal of fresh water. We're likely to use much more water for showering than at the kitchen sink.

It also has a 78 gal black tank.

Is there a way to connect the two grey water tanks together so that we can utilize some of the kitchen sink tank for the shower?

[bpounds]

I wouldn't want black contents in my gray tanks either. The lines for gray are usually smaller, 1-1/2" or 2" versus 3", and not designed to handle the solids and paper. But in practice, that isn't likely to happen unless you do so on purpose. Depends on how you use the tanks, and how they are plumbed in a particular unit, but if you give it some thought it won't be an issue. Just keep in mind that contents are not going to be sloshing back and forth between tanks. They are going to find a common level, the flow is slow, and that's about it really.

[one_strange_tex]

lakeside013104 wrote:

Butch50 wrote:
I have 2 grey tanks on my Grand Design Reflection and I put one of the end of the 3" dump line.

Valetrra

This allows me to keep this valve closed and open both grey tank valves to tie them together.

When I dump my tanks close both grey tank valves and hook the stinky slinky to the outlet then open the Valterra valve and then the black and let the black drain and then you have both grey's to empty to rinse the slinky.

The above mentioned system works great. I have the same set up.

I would NOT share black tank waste with grey tanks for any reason.
If you are concerned about too much black tank usage, do your business in the public CG facilities or if dry camping, use the woods. Let wife and kids use 5er facility. Just a thought.

Lakeside

I don't know about "for any reason," but I think diverting black water into grey tanks is not advisable for odor control around sinks and kitchens. As for us, our galley tank tends to fill first, then grey and black last. We do try to use the parks' facilities for, ahem, solid waste to lower volume and simplify waste handling.

Ditto for using the Valterra valve at the common curbside drain outlet to equalize tanks as needed and avoid that "surprise" when you remove the cap if any of the individual tank drains have leaked through.

[lakeside013104]

Butch50 wrote:
I have 2 grey tanks on my Grand Design Reflection and I put one of the end of the 3" dump line.

Valetrra

This allows me to keep this valve closed and open both grey tank valves to tie them together.

When I dump my tanks close both grey tank valves and hook the stinky slinky to the outlet then open the Valterra valve and then the black and let the black drain and then you have both grey's to empty to rinse the slinky.

The above mentioned system works great. I have the same set up.

I would NOT share black tank waste with grey tanks for any reason.
If you are concerned about too much black tank usage, do your business in the public CG facilities or if dry camping, use the woods. Let wife and kids use 5er facility. Just a thought.

Lakeside

[bpounds]

Not a great photo of the valve, too close, but notice the phillips head screw that I added behind the bayonet connector. This keeps it from falling off on the road, or too easily walking away with someone. Some guys probably just glue them on.

[RVhiker]

Like this valve: http://www.campingworld.com/shopping/item/twist-on-valve/27868. It fastens on to a common outlet connection for the grey tanks. CLOSE the twist on valve. OPEN the grey tank valves. Grey tank fluid seeks a common level and fluid flows from the fuller grey tank to the emptier one (if both tanks are at the same elevation).

When you dump with this in operation, connect to the twist on valve.

[MFL]

Page 1 Butch50 use clicky

Jerry

[Lexx]

Can someone post up a photo of what they mean by having a twist-on valve on the outlet? I'm not picturing how this outlet allows you to share between the two grey tanks. Thanks.

[bpounds]

I agree with those who suggested the twist-on valve on the outlet. As long as you have one common outlet for all the tanks, this is simple and so convenient. I can share between tanks, any tanks I choose, I can use gray water to back flush my black tank at dump time, and that extra valve between blissful dumps and catastrophic dumps, is a nice peace of mind. They should be standard equipment in my opinion.

[Dick_B]

A cheap way to accomplish the same thing is to put a valve on the sewer pipe outlet. When the shower tank gets high close the outlet valve and open both gray tank valves. They should balance out giving you more shower capacity. They you can close the gray tank valves.
We do this when necessary and it works out well.
Of course, another way is to chose a site with sewers...

Guess I should have read the previous posts for the same idea. Great minds....

[coolmom42]

If you ever get in a bind for gray tank space and the black still has a lot of room, you can drain the gray tank into a bucket and pour it down the toilet. Not convenient, but also serves the purpose of providing a forceful rinse-out to any solids accumulating at the toilet outlet.

[Second_Chance]

MFL wrote:
You can use a twist on valve at the main drain exit, if both gray tanks empty from there. You can just open both tank valves then to make one big gray tank.

Jerry

X2 ^^. This is what we've done with our GD Reflection. There are quite a few posts about this over on the Grand Design Owners' Forum.

Rob

P.S. - NEVER cross-contaminate your black and gray tanks.

[Bumpyroad]

Old-Biscuit wrote:
It's all 'waste'....grey tanks can be as nasty as black tank---even worst
Rotting food, rancid greases/oils, decaying hair, sloughed body cells etc .

I think adding a ton of poop to the equation makes the black a little worse. I think that if you were ever in an place that allows grey water to be dumped on surface, that they would fuss a bit if other "stuff" appeared in the grey water.
bumpy

[Lexx]

Hmm, the one way valve is an interesting idea.

[Old-Biscuit]

It's all 'waste'....grey tanks can be as nasty as black tank---even worst
Rotting food, rancid greases/oils, decaying hair, sloughed body cells etc

Past two trailers (1980 and 2007 models) I have added an 'extra' dump valve on the common drain header. With it closed I combined both black/grey on the 1980 trailer and all three (black/grey/galley) on present 2007 trailer)

Funny thing...no issues with odors (black or grey) cause the 'vapor barriers' as designed worked and dumping the waste tanks when FULL allowed for that WHOOSH factor (fast moving/high level river moves boulders)

If only the forward black/grey tanks share common drain header and rear grey has separate dump valve/line (as indicated by only one black/grey valve handles in wet bay center) then the extra valve on the forward common drain header will allow you to combine the forward black/grey 'waste' tanks.