Anyone add extra gray tank capacity to a Seneca?

[ralett]

We have a 2018.5 Seneca FS and do a lot of camping in places that do not have full hook ups. We carry extra water which is easy to siphon into the fresh tank, but we always have issues with the gray tank filling up too quickly. We deal with this in various ways but that fact is, it's inconvenient. 40 gallons of gray water is just not enough capacity for extended boon-docking.

I'm curious if anyone has added gray tank capacity to a Seneca and if so, how did you do that?

Thanks!

[oldmanAZ]

Not a Seneca only problem or solutions, but...
- some wash dishes in a plastic basin and dump the water into the toilet
- some drain some gray water into a bucket and dump that into the toilet
- some take showers standing in a plastic basin and dump that into the toilet.

Also, check with a local Ranger regarding the rules where you are boondocking. In some places it is permissible to dump gray water from dish washing basins etc. on the ground, but dumping gray water tanks is usually not permitted.

We've been stingy with our fresh water use and, so far, have not needed to resort to the above suggestions.

[MD3]

I've thought of using our macerator to pump gray into the black tank via the hose routed into the toilet as a last resort. We have a lot of black tank capacity.

I added a 58 gallon fresh water tank under our 2018 but I'm not sure how the 2018.5 is configured underneath. I'd bet you could find a place to add another tank somewhere underneath it or in a cargo area with some creative looking around.

Ronco Plastic makes all kind of shapes and sizes of tanks.
https://ronco-plastics.com/


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[Rustynuts]

We have a 2018.5 RB and this is one thing we considered when choosing a floor plan as it has 2 sets of tanks for a total of 80 gallons of gray and 56 gallons of black. We Boondock a lot also but we have been able to go 8 days with just the DW and I and being conservative.



I have done a lot of work on our RB and at least in our floor plan, I could easily replace the existing tank with a larger one with a little work. That or install a tank in the rear between the frame rails behind the fuel tank.

[qnghiem]

I carried 42 gal 4 wheeler tote. I can used trailer hitch toad to pull it to the dump station.

[pmdevries]

I've been meaning to post this modification, and MD3's post above has finally inspired me to do it. I've implemented a system where I can pump my gray water into my black tank using my macerator. This works for those that have a macerator.

I implemented a series of valves so I can direct the output of the macerator to a pipe that leads to and enters the black tank. I used a Uniseal for the pvc pipe to enter the black tank. Here's a link to the uniseal: https://www.plastic-mart.com/product...nouniseal-0100

I have used it several times and it works very well. No leaks. And of course, it's always good to add more water to the black tank. This allows us to go longer in boon docking situations since the gray always fills much faster than the black.

[Crossingover]

Originally Posted by pmdevries

I've been meaning to post this modification, and MD3's post above has finally inspired me to do it. I've implemented a system where I can pump my gray water into my black tank using my macerator. This works for those that have a macerator

That's ingenious! Thanks for sharing. We really appreciate our macerator and now you've given us another reason to recommend one.

[MD3]

I like the pipes into the black tank. That would be a lot easier than running an extension hose.



We also chose the 37RB for capacity when dry camping while offroading.

90 gallons of gray (40/50 tanks)
64 gallons of black (32/32 tanks)

129 gallons of fresh (I added a 58-gallon tank between the frame rails in the rear).

Ronco plastics was the go-to for tanks and a fraction of the price of others online. I called them and they were super helpful, great price, and put fittings exactly where I wanted them while I waited to walk away with it.


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[pmdevries]

Originally Posted by Crossingover

That's ingenious! Thanks for sharing. We really appreciate our macerator and now you've given us another reason to recommend one.

It's funny, when I was looking at this project last summer, I was trying to decide how I could transfer gray water to the black tank, how I would get a pipe from the gray to the black, pump needed, etc. Then staring me right in the face was the answer, the macerator could be my pump.

We love our macerator also. I think it's the cleanest, easiest way to empty the tanks I've come across yet.

[ebarchak]

Originally Posted by pmdevries

I've been meaning to post this modification, and MD3's post above has finally inspired me to do it. I've implemented a system where I can pump my gray water into my black tank using my macerator. This works for those that have a macerator.

I implemented a series of valves so I can direct the output of the macerator to a pipe that leads to and enters the black tank. I used a Uniseal for the pvc pipe to enter the black tank. Here's a link to the uniseal: https://www.plastic-mart.com/product...nouniseal-0100

I have used it several times and it works very well. No leaks. And of course, it's always good to add more water to the black tank. This allows us to go longer in boon docking situations since the gray always fills much faster than the black.

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This is a great mod and I am working on it now. How did you get the hose fitting off the macerator output? Did you cut it off?

Maybe the better question is how did you attach the PVC to the macerator output?

[MD3]

Originally Posted by ebarchak

This is a great mod and I am working on it now. How did you get the hose fitting off the macerator output? Did you cut it off?

Maybe the better question is how did you attach the PVC to the macerator output?

The fitting coming off the macerator is threaded.... it unscrews.
PVC pipe adapter then threads on.

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[ebarchak]

Originally Posted by MD3

The fitting coming off the macerator is threaded.... it unscrews.
PVC pipe adapter then threads on.

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Mine appears to be a slip joint and it is glued on. I have figured out how to do it. The hose barb coming off is 1 1/4” and the macerator output is 1 1/2”. I am going to leave the barb attached and use a reducer to go from 1 1/4” to 1 1/2” on the barb and seal with silicone. Then I can build out the valve assembly.

[MD3]

Originally Posted by pmdevries

Here's a link to the uniseal: https://www.plastic-mart.com/product...nouniseal-0100

I've been thinking about bridging our 2 gray tanks. This uniseal might be an easy way to do it. Put a connector pipe near the top of the tanks so when the rear (shower) tank gets full it will over flow into the front tank.

Any ideas or thoughts.... am I missing anything with something like this ?

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[pmdevries]

As MD3 stated, mine was also a threaded adapter. This is the fitting I used to re-connect to the macerator:

https://www.pvcfittingsonline.com/1-...t-461-015.html

I have not had any issues with the uniseals and think they are a great inexpensive way to connect pipe to the tanks.

[ebarchak]

2021 37TS. Finished this mod yesterday. Took less than two hours. It took longer to find all of the parts needed at Lowe’s. Ordered Uniseal from Amazon (B00A8HWKS0).

I thought about using PEX to do this, but went with PVC. A little tricky running the 1 inch PVC behind the Nautilus because the Y adapter comes into macerator slanted towards the door. I used a 45 PVC joint.

My OEM macerator hose was attached to a barb cemented to the macerator output (could not remove). I used a reducer and silicone caulk to join the T to the output barb.

Looking forward to testing this week. Now I have 90 gallons for gray and black with a max of 50 black. If I want 60 gray and 30 black I can do it. Based on the manual, I am estimating 13-15 GPM flow rate from gray to black tank. So I can set valves, pull gray knife and turn on macerator for about 1+30 minutes to transfer 20 gallons of gray to black tank. 50 black and 40 gray just does not make sense for us.

During this install I noticed the black tank is not supported above the frame rails, just like the fresh water tank. The hard plastic is pushed down to the frame rails (last picture). It is crimping the same wire bundles just like the fresh water tank.

[Bruceter]

(Quote)
During this install I noticed the black tank is not supported above the frame rails, just like the fresh water tank. The hard plastic is pushed down to the frame rails (last picture). It is crimping the same wire bundles just like the fresh water tank.
(End quote)

Can anyone explain exactly what theses styrofoam blocks are supposed to be doing?
The black tanks are mounted along both front and rear edges for the full length of the tank. I believe when the tank starts filling theses randomly placed blocks create a bulge up into the bottom of the tank which in turn starts to create the dreaded poop pyramid below the toilet. I noticed mine was the same way, the styrofoam was sitting on the wire harness running through the compartment. I did rearrange the blocks but when I pulled them out I noticed the tank had a permanent concave bulge pushing up into the tank.

[Grumpy]

Originally Posted by Bruceter

(Quote)
Can anyone explain exactly what theses styrofoam blocks are supposed to be doing?

Just to help support the tank when full. Had the same thing with our 08.

[ALJO]

Great engineering design

[Scoutmaster253]

Originally Posted by ALJO

Great engineering design

x2