I've heard about odor issues when marine heads are plumbed with salt water. Wondering if a porta potty (a Thetford 550P MSD, if it matters) would be troubled with the same issue.
Salt water in a porta potty?
- Thread starter Gene Neill
- Start date
It’s mostly the critters sitting in the intake line over several days/weeks; dying and then rotting. Easily fixed by doing a fresh water rinse of that line before leaving for the week. But I’m not sure how the Thetford Porta potty is plumbed.
Gene... Your "Porta Potty" is like a bucket with a lid. File a bucket of sea water and put a sealed lid on it, you know like one of those box store buckets. Let it stand out in the sun for a couple of days. Then go pop the lid. I suspect you'll get your answer.
No, it is the sulfate in the seawater that makes the stink (bacteria convert it to sulfide). A common misconception. But the result is the same.
Interestingly, but not surprisingly, the treatments that work in holding tanks are all wrong for portables. The holding time is less and there is no ventilation. All new rules. Saltwater still hurts.
https://www.practical-sailor.com/issues/44_9/features/Controlling-Porta-Potty-Odor_12472-1.html
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You think seawater will make a difference?
Sorry. Had to point out the obvious, having done side-by-side testing.
I grew up on a milk farm where foul odors were abundant. Our 1991 boat uses sea water for flushing. Other than the first flush after months of stewing, the head systems are pretty much odorless in operation.
I really need to subscribe to PS, so I can read that article ... and so many others. Think I'll do that after work this evening.
Ah, so, it's not the odor from the holding tank I need to be concerned with in this case, but the odor from the "fresh" water tank?
That would make sense. For many years I was very "into" saltwater aquariums, which stink to high heaven after 24 hours without electricity, to circulate the water and keep the beneficial bacteria alive.
Sort of like a household toilet that opens directly into the septic tank, with no trap between, just a large gate valve. And with enough water in the reservoir to flush the toilet for several days.
All MSD portapotties have just two hose connections--a pumpout line and a vent line...no other plumbing unless you want to install a y-valve and macerator pump in the pumpout line to let you dump it at sea. So there is no intake line...you fill the reservoir manually with a hose or a pitcher/jug of water. Because MSD portapotties are vented same as any other holding tank, the same tank product--No-Flex, for example--that works in a holding tank will work equally well in an MSD portapotty.
However, the tanks on portable models are sealed, creating an anaerobic environment in the tank that won't let ANY tank product eliminate odor or break down solids and TP.
I don't know why it should ever be necessary to fill the reservoir for either type of portapotty with sea water...fill with a hose at the dock before you leave. If you dump at sea, carry a few gallon milk jugs of fresh water to refill it. Using sea water can create sea water mineral buildup in the reservoir and tank that can clog the flush valve.
The tank in both versions should be rinsed out fairly often...it's not hard to do: Use a hose or pour a bucketful of clean FRESH water into the tank (hold the flush lever open while you do this) while the tank is being pumped out. That does require using a dockside pumpout instead of a pumpout service that comes to your boat unless someone can be on the boat when they're there.
So best to fill at the dock where you can use a hose. Portapotties are designed to for the tank to be full at about the same time the water in the reservoir exhausted.
--Peggie