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Class A Diesel-Gray Tank

rickvikki
Explorer
Explorer
Hello everyone: Just looking for opinions on whether you should or should not leave the gray tank open while parked with full service hookups?

Thanks, Vikki and Rick
Rick and Vikki Landry
Ottawa, Canada
Tiffen Phaeton 2006 (40 ft.)
34 REPLIES 34

xctraveler
Explorer
Explorer
What is a sewer fly? never heard of them except on this forum, never saw one. Are they like left handed smoke shifters? Or snipes?
Paul
2012 Phaeton 36QSH on Freightliner Chassis with a Cummins 380 pushing it. 2011 Cherry Red Jeep Wrangler Rubicon with US Gear Unified Tow Brake System. Check out my blog
FMCA 352081 SKP# 99526

Beltone_Magoo
Explorer
Explorer
With the valve open just wait until you pick up a load of those little black sewer flies. They are also called something else but are a real nuisance nonetheless.
Good luck and safe travels!
Doug & Connie
2001 Holiday Rambler Imperial
2001 Subaru Forester toad

uncle_t
Explorer
Explorer
leave it open and you get to allow grease,soap,small solids to build up and perhaps harden in the bottom of your tank. you also allow sewer gases and sewer flies to get into your tank and into your coach if a p trap dries out. all of this makes rv life better. and besides dumping it every few days is such an inconvenience.:W
2020 Integra 36U
can am spyder or can am commander
BE PREPARED- NEVER BRING A KNIFE TO A GUNFIGHT.

MeanderMan
Explorer
Explorer
Full timing for nine years and leave it open. With p-traps on all your drains and additional one in your sewer hose you don't have to worry about "gas" and "flies" - although I've never heard of anyone having these problems. Periodically we pour a cup of dishwasher detergent into the grey tank with a few gallons of warm water just before travel. The solution will clean the tank and prevent any buildup.
Happily Fulltiming Somewhere
2006 Itasca Ellipse 40FD
2013 Honda CRV
Our RV Blog

PSU_RVr
Explorer
Explorer
I leave it open. I also leave a trap in the hose before it goes into the camp drain to prevent gases from coming back. But I didn't have a real reason for doing it until I learned about the flies. Never thought of that, but makes for a good reason.
Newmar Canyon Star 3920 Toy Hauler
Where it's been, the crew -Bandit, Morgan, Sherman. It:

mayo30
Explorer
Explorer
Sounds like some of our bored happy campers flushed their meds by accident.Lap on boys.

Smitty77
Explorer
Explorer
Mr.Mark wrote:
We leave the valves closed most of the time. If we run the washer and go out to lunch, etc., I'll open the gray tank as not to let it over fill. We have a 70 gallon grey tank so there is plenty of room.

But, I always plan on the gray tank being almost full when it's time to dump the black tank. It just makes for a better cleaning of the sewer hose after the black tank is emptied.

MM.


Open? Closed? As in many things with RV'ing - it depends! If your are staying somewhere for a few months, then leaving the Grey open for longer periods is probably not going to hurt you too much. Factor the scum/residue build up as others have pointed out. If you are a 'few days in a park' and then go kind of traveler, then we following Mark's way is a good way to go.

After fighting to clear out a pyramid when we bought our first new used Bounder in 2006, I very carefully administer the tanks!

We try to get at least 1/2 tank of Black before draining, running dumping water in as needed to get it to that level.

For us, typically:

Grey we keep closed until needing to dump, and when we are close to leaving, we work it to time it to be 3/4 full before the final dump and go...

Except when Boondocking, we try to not travel with tanks too full. If we know we've an easy route, and short distance to our next stop - we will sometimes travel with a 1/4 tank or under Black.

Yep, it depends!

Best to all, and what a great invention the tank flushers were!!!
Smitty

wny_pat1
Explorer
Explorer
Both of mine are closed until it is necessary to dump. Then I dump the black and flush with the grey.
โ€œAll journeys have secret destinations of which the traveler is unaware.โ€

RandandDoug
Explorer
Explorer
Only leave the grey open when traveling down the road!!:E


Hope everyone knows that is a joke?!?!?!? hahahaha

Mr_Mark1
Explorer
Explorer
We leave the valves closed most of the time. If we run the washer and go out to lunch, etc., I'll open the gray tank as not to let it over fill. We have a 70 gallon grey tank so there is plenty of room.

But, I always plan on the gray tank being almost full when it's time to dump the black tank. It just makes for a better cleaning of the sewer hose after the black tank is emptied.

MM.
Mr.Mark
2021.5 Pleasure Way Plateau FL Class-B on the Sprinter Chassis
2018 Mini Cooper Hardtop Coupe, 2 dr., 6-speed manual
(SOLD) 2015 Prevost Liberty Coach, 45 ft, 500 hp Volvo
(SOLD) 2008 Monaco Dynasty, 42 ft, 425 hp Cummins

Rollnhome
Explorer
Explorer
Thanks Ohhwell. Your not going to get this type or level of information on the other RV/Camping forums.
2008 Discovery 40X towing a Jeep Grand Cherokee

OhhWell
Explorer
Explorer
Rollnhome wrote:
OhhWell wrote:
I keep the grey 75% open and the black 3.766565% open. Then 4 hours before it is time to go, I close the grey by 47% and open the black by .0008%. When it is time to go, I open both of them then run around the RV singing Dixie for 6 laps. After that, I have perfectly clean black and grey tanks and never use any chemicals.... ever.


I see you have a 36 footer. I have a 40 footer. Do you think I could get by with 5 laps? If I did 6 I'd probably need a nap. Maybe I could get the wife to run'em, just a thought.


Well, by my estimate, I probably average 4.5 mph while running around the rig considering slowing down some for corners and cover the 534' of those 6 laps in roughly 81 seconds. Since slides would be in, your 4 laps on the 40' rig would be about 484' total so as long as you average about 4.07 mph, you should be good.
1998 bounder 36s V10 F53

Rollnhome
Explorer
Explorer
OhhWell wrote:
I keep the grey 75% open and the black 3.766565% open. Then 4 hours before it is time to go, I close the grey by 47% and open the black by .0008%. When it is time to go, I open both of them then run around the RV singing Dixie for 6 laps. After that, I have perfectly clean black and grey tanks and never use any chemicals.... ever.


I see you have a 36 footer. I have a 40 footer. Do you think I could get by with 5 laps? If I did 6 I'd probably need a nap. Maybe I could get the wife to run'em, just a thought.
2008 Discovery 40X towing a Jeep Grand Cherokee

down_home
Explorer II
Explorer II
We have when staying for more than a couple of days. When using the washer/dryer we leave it open.
I encountered large slugs, in Mississippi, in the campground connector.
Didn't even connect the hose, which we do to speed up emptying the next day when we leave, if just staying for the night.
Some have encountered sewer flies etc.
If in doubt I won't. Might be the best idea not too.