Recirculating / Gravity Toilet or ?

**Camping Carpenters** · 09-02-2018, 02:06 PM

We just purchased a 2005 2720SD. At some point, the Thetford Recirc. toilet was replaced with the Dometic SeaLand with a 9.5 gal. tank. We have owned a few RV's; our last had a 25 gal black tank - so 9.5 gal seems small (we carry a 22 gal Barker with us to dump during camping). We haven't used a recirculating toilet, but are thinking of replacing the SeaLand with one.
What are the pros and cons with recirculating toilets? Which do you all prefer - recirulating or gravity or something else? Does anyone know a way to add a black tank underneath, next to the gray tank? What other alternatives are there? Thanks in advance to any experienced TM owner who has input.

Shane826 · 09-02-2018, 09:16 PM

Wow you’d be the first to go from the SeaLand to the Dometic. Lots of people out there would be happy to trade with you.

**Bill** · 09-03-2018, 06:04 AM

On this forum, no topic has been discussed more than the toilet. I think it is fair to say that most owners are satisfied with the recirculating toilet, but a sizable and more vocal minority don't like it and are willing to spend more than $1000 to replace it. There are two or three favored replacement toilets, and if you read down through the Plumbing Forum, you will find them and their stories. Because the replacements are expensive, Shane is right - you might very well be able to work a trade with someone who has a Thetford and wants a SeaLand. Shipping cost might be a bit, but you would still come out ahead.

If you decide you want to go ahead with this, why don't you post an ad in the TM Parts Wanted sub-forum near the bottom of the page. You should probably mention a time frame for the trade, any cash that you would expect to change hands in either direction, and most important, your zip code so you can get a feeling for the shipping cost. Maybe, just maybe, you could arrange for a face-to-face trade and eliminate shipping cost entirely.

Let us know where you go with this, and how it works out.

Bill

**Camping Carpenters** · 09-03-2018, 07:04 AM

Thanks, Shane and Bill. We would probably purchase a new Thetford, rather than trade. I've looked through the forum already. Just looking for some overall ideas. I would love to pipe a small black tank in under the frame, don't know if that's viable, so ideas in that direction would be helpful.

oldstick · 09-03-2018, 07:55 AM

You are correct, the 9.5 capacity of the Sealand is not a perfect solution. The two of us can fill it up pretty easily within 3 days. (Yes, we're full of it... haha).

But correct me, if I'm wrong, the original Thetford is even smaller in capacity? I would not spend any money to change it back, other than if you do figure out a way to add an additional holding tank underneath.

**Camping Carpenters** · 09-03-2018, 08:19 AM

As I understand it, a Recirculating toilet is more "efficient" in volume use than a conventional gravity feed. If I keep my SeaLand, I would like to add additional black volume to supplement the 9 1/2 gal, somehow below the frame.

**dab1950** · 09-03-2018, 09:30 AM

I'm definitely in the group that hates the Thetford Electra-magic recirculating
toilet. Do not recommend you convert back to it. Most likely couldn't find a
new one anyway.
The easiest solution to what you've asked, is adding additional 3" pipe under
the TM in a long loop between the elbow under your Sealand and the dump
gate. Contact another member and friend of mine, Paul (pmhellings) as he
swapped out his old recirc with a Sealand equivalent plus added the additional
piping for more black water storage under the TM. There might be other
threads in the plumbing forum about this 'added black water capacity' topic.
But you will need to join the forum to be able to use the full search capability.
Joining the forum is only $12/year but most will agree, it's the best $12 spent!
Congrats on your new to you TM.

**Bill** · 09-03-2018, 11:15 AM

Quote:

I'm definitely in the group that hates the Thetford Electra-magic recirculating toilet.

See what I mean about "more vocal"?

Quote:

Most likely couldn't find a new one anyway.

The Thetford Model 80 is readily available for about $500, the Sealand 711 costs about the same.

Quote:

As I understand it, a Recirculating toilet is more "efficient" in volume use than a conventional gravity feed.

You are correct. The Thetford has a 6- or 7-gallon tank (depends on who you ask). You precharge it with about a gallon of water, and from then on, the only thing you add is pee or poo - no more water goes into the tank. With a conventional gravity toilet, you add water to the tank every time you flush, and that water consumes tank capacity.

The gravity toilet operates like the one in your home. You put 6 ounces of pee in the bowl, and when you hit the flush handle, it takes 2 gallons of water to wash away those 6 ounces. In an RV, the numbers aren't quite so lopsided, but the idea is the same. According to the Sealand Owner's Manual, it uses about a quart of water (32 ounces) to flush away those 6 ounces.

Finally, re adding black tank capacity, dab1950 is exactly right. People have been trying since the beginning of this forum to find a way to add capacity, and the best (and as far as I know, only) way is to add the serpentine pipe wherever you can find room under the TM. If you do this, be sure to slant the pipe toward the outlet, and be sure to use a removable cap at the uphill end.

Bill

Larryjb · 09-03-2018, 09:10 PM

The biggest complaint about the recirculating toilet is smell. I recently read that if it smells, use more Thetford Blue (the stuff with formaldehyde).

Everytime someone added something to make the toilet smelly, I added more Blue. If someone complained about smell, I added more Blue. We used alot of Blue, but the smell was acceptable.

Our issue has been with solids not flushing well. Bill once suggested using baby oil before #2's. This works quite well. We do find that as the toilet approaches full, solids don't flush as well.

With a family of 4, we got away with about 3-4 days between dumping.

We are happy with ours.

Shane826 · 09-04-2018, 06:12 AM

If you really want to try a Thetford recirculating toilet, you can have mine (we switched to the SeaLand) for the cost of shipping. Set it up, use it, and decide for yourself. Then if you hate it you can go back to the SeaLand. If you decide to keep the Thetford all I ask is you pass your SeaLand on to someone else.

Here’s my take on the toilet situation... I never had a smell issue with the Thetford. But we almost always camp with full hookups, so I dumped it at the most every other day. Solids required a “poopstick” to help flush, usually used a plastic knife. My issue was understanding how it works, I just found it gross. Also no water in the bowl led to “splash back” when going #1.

Is the SeaLand perfect? No. The “flush” seems kinda weak (maybe that’s all RV toilets) and it’s kinda hard to rinse the tank clean. If you boondock (again, we like our full hookup RV parks), water becomes an issue. I find that we fill the SeaLand a lot quicker than we did the Thetford (never actually filled the Thetford, dumped it as a pre-emptive strike) but we also use the SeaLand a lot more. With the Thetford it was really for overnight and emergencies. Otherwise we used the campground facilities. But there is ZERO smell. I still use a shot of Thetford Aqua-Kem in the tank. Also traveling without dumping is no longer a concern because the tank is isolated.

Let me know if you’re interested. My old Thetford works perfectly, at least as well as it was designed. I held onto it for someone who needed a replacement. Have had a couple inquiries but nobody has pulled the trigger.