Grey/Black mod

[bargeman]

Has anyone here considered or performed a mod that allows you to pump grey tank content into the black tank?
My grey fills in 3 - 4 days and my black will be less than 1/4. Considering ways to get more mileage on grey water use...

[ModestMonk]

This is how to do it: here

We intend on using a dry toilet so the black would be dormant, better to join and extend the trip.

[twogypsies]

For one, you could try to conserve on your grey water use. Shorter showers and turning water off inbetween soaping and rinsing; don't leave water run when brushing teeth, washing hands; minimal dish water and then dump it into the toilet afterward and you don't have to do dishes after every meal; pots? wipe them out and reuse them; could also use paper plates. All these will help immensely.

[Just For Fun]

Originally Posted by bargeman

Has anyone here considered or performed a mod that allows you to pump grey tank content into the black tank?
My grey fills in 3 - 4 days and my black will be less than 1/4. Considering ways to get more mileage on grey water use...

IMHO the immediate problem with this idea is that you would not lengthen your time (boondocking) but rather shorten it by filling your Black tank sooner.

[charles tuit]

Originally Posted by bargeman

Has anyone here considered or performed a mod that allows you to pump grey tank content into the black tank?
My grey fills in 3 - 4 days and my black will be less than 1/4. Considering ways to get more mileage on grey water use...

I made a transfer unit out of a 12V water pump. Made 2 short hoses out of a old garden hose to connect one to a Valvec cap with a hose fitting on the dump valve, and the other to the black tank flush inlet. The pump is a 2.8 GPM, so to transfer 10 gallons I run it approximately 4 minutes. I wired a 12V cigar connecter from the light in the wet bay.

Hope this helps.

[wa8yxm]

I do not have that problem and thus don't do the transfer but I have the hardware.

I have a Flo-Jet macerator pump.. and 50 feet of Black (As well as 25 of Gray) 3/4 inch garden hose... I have 3 tanks, black, Gray, and Wash (Gray 2).. You can likely figure out the hose use.. (black for black)

Well you'd not need that much hose but run it back indoors and stick it in the toilet...

How I use mine.

Normally I'm using the 3" stinky slinky to dump the two "Main" tanks (Black and Gray 1) I use the GRAY hose from an adapter cap on Gray 2 to the 3/4" fitting on the elbow (Flush fitting, I had to drill it out of course) or.. Read on for when I'm using the pump.

However on some sites there is a problem doing that.. For example
It's a long way to the dump hole, a long way to flow, it's a long way to the dump hole and perhaps up hill to boot.

So then I use the macerator and the 50 footer... If I'm going to be there long enough to "hook up" not just Hook to dump.. I have a "Ground adapter" based on teh drop in sewer "plugs" I see in many parks.

A plastic flower pot filled with concrete.. And a 3/4" PVC Pipe.. no if I was re-doing it I'd put in 2 pipes. but that's another story

At the top of the pipe is a "T" fitting.. one side has the matching hose adapter for use with the pump, the other side has a Short pipe (Nipple) to an Elbow to another short pipe and Elbow to flapper valve (Gravity check) to another hose adapter.. On some sites I hook the gray hose to the check valve (So black can't back flow) and it works.. if I had it to do again as I said I'd use two pipes and forgo the check.. But I had the check on hand anyway so no loss there.

The check valve is also the lift handle.

Works great... I don't use the pump often, but when I do, works great.

[luckyd]

Dishes and showers are the biggest use of the grey tank.
Either do dishes once per day or put a plastic tub in the
sink and flush down the toilet after doing dishes.

Learn to take shorter showers or shut off water while soaping down.

Guess it all boils down to what you WANT to do.

While boondocking we use paper plates and the barbecue a lot more.
We will also prepare soups, stews, chilli, spaghetti, and put them into
freezer bags. They can then be frozen flat which takes up a lot less
room in the freezer.

[Smitty77]

We did this with first our Bounder, and now our Country Coach.

On the Bounder, due to tank and venting access, we spliced into the Grey at about 1/3 of the way from the bottom of the tank. Then fed into the black at about as close to the top as we could get.

On the Country Coach, same with the Grey about 1/3 of the way from the bottom, and then the black was fed into the Blacks venting pipe.

Both used the OEM Shure water pump, with a newer improved water pump going into 'fresh' water pumping duty.

We also added an inline filter screen between the Grey and the pumps (Grey to Black now.) inlet side. I added the cleaning of that filter to our regular maintenance schedule.

One thing that was interesting to find out, was that both I and the place that sold me the Country Coach from consignment (A Southern California CC dealer.) - was that after we completed the installation. The tech said 'Lot's of work for a 40 gallon black.'... When I negotiated the price on the coach, it included 100 hours of shop work at the dealers base rate (Break even vs the then $125 shop rate. It was either $70 or $75 for labor. Plus I got the parts a price, plus 5% to cover dealer handling of the parts. We knew we would be making mod's, so baked that into the deal. Took the Salesman two days to beat the Service Manager (Who inside of the Dealer, took the budget hit for the discounts. Vs the Sales Department!) into agreement...). The Salesman, an stand up honest gent (They do exist!) and the Service Manger, and myself - all thought we had a 60 gallon Black. We called then just reopening CC to ask, and the tracked down our coach number and confirmed the Tech was correct, only 40 gallon.

We still find that while boon docking, that the ability to move Grey to Black, extends our days off the grid by two more days.

I feel for those that do stay off the grid for longer periods, that this is a worthwhile mod.

Best to all,
Smitty

[WendyG]

I thought I was going to do this mod, but no longer think I will do so. We use campground showers if we can. If we use the shower in our rig, We limit the water use best we can and also dump dishwater and rinse water down the toilet; that seems to help balance our tank levels quite a bit. And we have gotten much better at conserving grey water. A bottle of Purell hand sanitizer helped quite a bit for minor, water free hand clean ups. If I really needed to transfer more grey to black, I'd probably carry a bucket of grey to the toilet...not fun but doable...it has not come to that yet, so just as well that we waited to do the mod.

[RV Vagabond]

https://www.youtube.com/watch?v=W28pNmbnBZI

[Cranemec]

Get Tecma toilets. Problem solved. Your black tank will fill up nice and quick. Lol.

[beenthere]

on our alfa gold we have electric dump valves and a manual valve after the electricts..and our grey tank is above the black.. so this could be used in your case, if tanks are stacked as they should be.. when i dump i of course do black first then close the end valve and open the grey with the black open and it fill up the black, of course i dont use all of it as i want some for cleaning..so if i ever have a full problem i do the will same..

[pcurt23]

Originally Posted by bargeman

Has anyone here considered or performed a mod that allows you to pump grey tank content into the black tank?
My grey fills in 3 - 4 days and my black will be less than 1/4. Considering ways to get more mileage on grey water use...

My system is very simple. I use a clean dump macerator and the way it is connected makes it a closed system. I open the grey tank (with the clean dump valve closed) and then I open the black tank valve and the water pressure of the grey tank equalizes into the black tank. I get about 25 extra gallons of grey water into the black tank.