Gray overflow to black?

[chriscowles]

We have 1 gray tank and 1 blank tank, both 36 gallons. We typically will fill the gray tank well before the black tank. Having a practical means of shifting some gray drainage into the black tank would be useful, but I'd rather not do that manually with buckets, trekking it into the toilet.

In another thread I saw a reference to plumbing mods to allow shifting some gray water overflow to the black water tank. I used search and browsed lots of thread but can't find any mention of such a modification. Can someone point me to a description?

Thanks

[Prothos]

no mods yet i just take a 5 gal bucket and either dump the gray down my potty if boon docking or down the bath house if camping. i would be interested in maybe adding a mod if it did not take major changes

[youroo]

Water and ?? seeks its own level! Trying to balance both tanks is a (Messy) idea with very Little gain! Youroo!!

[chriscowles]

I'm skeptical, too, but am willing to consider the option if someone else invented a way. There are geniuses among us.

[Dave_Monica]

I don't see anyway to cross-connect the two tanks without contamination of one to the other ie black into gray. The bucket method may be low tech but it's the best solution.


Dave

[chriscowles]

When dumping full tanks I briefly hold both camera open but only after the black tank is fully drained and the gray tank is still full. I then close the gray valve promptly and allow the black tank to drain again. After that I close the black valve and don't allow communication between the two. Any further rinsing of the black tank is by way of a clear segment with attached hose.

[vinmaker]

The most practical way would be to simply install a connection hose from the grey to the black. As was pointed out, water will seek its own level. You therefore need to pump the grey water up and out of the tank and then deposit it into the black. This is really a simple Mod. Just need a bit of hose and a small pump.

Vin.

[SULTINI]

Really don't want to cross connect the gray and black. Keep two separate systems. GOD forbid somehow a cross connect and blocked black tank sewage will flow up into the shower, sinks etc.

[ependydad]

Warnings aside, I've read of other folks using a valve at the sewer connection and using it to equalize the tanks:



I've never done it, though.

[chriscowles]

I do something like that by opening the gray valve after the black tank is empty but only if the gray tank is relatively full, to reduce the likelihood of backwash.

[vinmaker]

Originally Posted by SULTINI

Really don't want to cross connect the gray and black. Keep two separate systems. GOD forbid somehow a cross connect and blocked black tank sewage will flow up into the shower, sinks etc.

Right. That would be another issue.

[SULTINI]

Originally Posted by chriscowles

I do something like that by opening the gray valve after the black tank is empty but only if the gray tank is relatively full, to reduce the likelihood of backwash.

Me Too

[hbillsmith]

I have 2 gray tanks. 50 gal each, 1 is kitchen, 1 is Bath/shower. Bath tank fills in a couple days, kitchen in a couple weeks (we use a small tub to wash dishes and dump it outside cause we dont want food remnants in our linescthat would build up or attract bugs). Read somewhere to keep dump cap on and open both greys so theycwould level out. Tried it once and what happened was both greys emptied and leaked over into the closed black tank which immediately showed full. No nasties because we werent using the black yet. I may have a black valve leak on this new 5er.

[Ryno22980]

RV Grey Water Potty Flush | ModMyRV

I'm thinking this might be the mod the original poster was talking about. Cool idea, but a bit more work than I'm willing to do. The bucket method will continue for me.

[chriscowles]

I did see that and agree it's overkill but was referring to this thread on this FR site. The reference was vague, which is why I asked. It sounded to me like the overflow was passive but would have to be one-way.

I guess I could inquire with the member who posted that comment but I only just found it again.

EDIT: I tried to reply to the thread but it's ancient, and closed. Also, the member (Triguy) hasn't posted a message since August. I sent a PM in the hope that he's still around. Maybe others here will recall that topic and know what he was referring to.