Fresh Water or Salt Water to flush the toilet?

[Nicholson58]

Originally Posted by Freedom45

We use fresh only.
Yes, one might have less odor but more important to me is no build up that develops in the discharge hoses and holding tank.

Totally agree. Marine heads are trouble enough without calcium and other deposits. Fresh only.

[Amapola]

Fresh water.

[skipperguy]

Used salt water for 26 years on same vessel. Added deodorizer from walmart camping dept once with every pump out. Never a problem.

[sandymwp]

Fresh water....on our boat for a month....6 heads....no odor as long as some clean water was in the bottom of the bowl after flushing, so as not to allow gases to come up.

[Stu Jackson]

Originally Posted by sandymwp

Fresh water....on our boat for a month....6 heads....no odor as long as some clean water was in the bottom of the bowl after flushing, so as not to allow gases to come up.

Are these manual toilets?


If so, that's not how they work.

[CassidyNZ]

Originally Posted by Stu Jackson

My experience is that the reality is that if you use your head on a daily basis, you won't get a stink from the incoming salt water. It's only when the salt water sits in the intake line for over a few days. Once you keep using the head the salt water doesn't sit in the intake line and "fester."

Quite right. Because it is a far smaller amount of salt water, most will experience the same smell from the first pump of a salt water faucet/pump but only momentarily. Excellent evidence that the smell has nothing to do with flushing the head. The good thing about this odor is that it is instantly perishable- it’s gone in seconds so I wonder why anyone worries about it.

The other thing experience has taught me is that the calcium build-up is about urine, not about water quality. And diet has a lot to do with the calcium too. Another post spoke of using vinegar to dissolve the calcium. That works quite well if left in the pipes for a while.

I have a question though. Seems from discussion that everyone has just one route for toilet waste and that is to a holding tank. Is that right? Because I have a two-way valve on both our heads that we switch when processing solids. If it’s just urine, we pump to the sea. That way we don’t squander holding tank space with just, essentially, water. Also, on passages, once we’re a couple of miles off-shore, we don’t pump to a holding tank at all. In fact whilst offshore I macerate the holding tank contents into the sea as well. Am I killing the planet?

Oh, and we only use salt water. Never have any problems with rubbers, valves, pumps, etc.

[sandymwp]

Our heads are electric.

[FlyingScot]

I recommend what we do:
Generous flushing time.
Fresh water when leaving the boat for more than a day or so.
Also drink a lot of fluids.

[Fbfisher]

Fresh water electric heads were a nonnegotiable when we were looking at boats to buy.

[Seasure Marine]

My recommendation on this topic for true offshore cruisers is simply to carry an
abundance of cheap white spirit vinegar. It is the only substance that I know of that breaks down uric acid and calcium without any harm to the equipment and it works fairly quickly.
Periodically fill the bowl totally, allow to remain for 10 minutes, then empty the bowl and immediately close the overboard valve so that the vinegar remains in the discharge pipe. After an hour or two, open the valve and pump over board. When using a black tank simply fill it with this cheap liquid once a year and allow it to remain for a few days or even a week and voila all nasties will be pumped out when you empty it.
It is also great for general wiping down of vessel interiors to prevent or remove mould.
Fair winds to all, Mike.
Michael Lavery SEASURE MARINE.

[Jolly Roger]

You can do both; Take a look at this on my website, or read it in last months SAIL magazine.
Installing two electric toilets

[mikereed100]

Maybe Thinwater will chime in here, but I seem to remember Practical Sailor did a test of the effect of different liquids on joker valves. I seem to recall that vinegar damaged the rubber with time.

FWIW I have always used salt water and never had a problem with odors, but we live aboard and use the head daily.

[thinwater]

Originally Posted by Coast Wanderer

Tudorsailor, I'm curious about what effect vinegar has on the waste breakdown process in the tank. Seems like if anything, it would help..

No, it is actually a slight negative (I design wastewater plants for a living). It lowers the pH, which is bad in terms of both odor and digestion rate. But the amounts used are too small to make an important difference.

[thinwater]

Originally Posted by mikereed100

Maybe Thinwater will chime in here, but I seem to remember Practical Sailor did a test of the effect of different liquids on joker valves. I seem to recall that vinegar damaged the rubber with time.

FWIW I have always used salt water and never had a problem with odors, but we live aboard and use the head daily.

The effect of vinegar was minimal, but not good. It is also barely effective at removing scale.


CLR is less harmfull, many times faster at removing scale (diluted 8x for use), and is several times the price as typically used. But in terms of price/scale removed, it is considerably cheaper, because it actually works.


Sew Clean / Barnacle Buster is another good choice. Fast and harmless to head materials.


Joker Valve Article, July 2013

Acids: We soaked the valves in diluted CLR, Lime-Away (sulfamic acid cleaner), vinegar, and 3-percent hydrochloric acid (diluted to 1 percent HCl) for a month. Vinegar caused minor and apparently harmless swelling in the neoprene valve, but not the nitrile valves. CLR caused significantly less swelling than vinegar and removed the lime several times faster, with less residue. Lime-Away damaged the nitrile valve, so don’t use this product in marine heads. Hydrochloric acid works fast and did not damage the rubber, but it is nasty to work with and it’s difficult to judge the dosage. Acid cleaning did not restore resiliency lost in the Raritan valve due to urine exposure. We recommend only CLR for acid cleaning.

De-Scaler Article, August 2017

White Vinegar The slowest of the slow, the best we can say is that it’s inexpensive, easy to use, and aluminum-safe. Unfortunately, there are downsides. It was the most aggressive towards steel on a mil/cleaning time basis, the scale removal was glacially slow, accomplishing little even with an overnight soaking, and a number of cruisers reported giving up on vinegar as a preventative method after becoming unconvinced it didn’t do much.
Bottom Line: Save the white vinegar for your salad.
CLR

Being dubbed the fastest acting of the slow group sounds like a dubious distinction, but this familiar product from Jelmar wasn’t that slow, and it did the least damage to aluminum parts for a given amount of calcium removal. On the other hand, it was the safest effective product for descaling an outboard motor.

Like all of the slow-acting products, there is no objectionable odor, and though you should keep all descaling chemicals off your skin, it is relatively safe, no more dangerous than many strong cleaners. Internal sacrificial anodes do not seem to interfere significantly, although removing them may is a good idea for longer soaks.
Bottom Line: This is our Best Choice for cleaning aluminum-containing systems.

Sew Clean

Based on phosphoric acid, Trac Ecological’s Sew Clean was the fastest and most effective descaler of the group. There is no objectionable odor, it is somewhat less acidic than muriatic acid, making it a bit safer around metals and skin. Although not as damaging to aluminum as muriatic acid, it’s still not something we’d want to leave inside an outboard engine for longer than required.
Bottom Line: Recommended. This is the best choice to remove heavy scale deposits from sanitary systems.
Barnacle Buster

Similar to Sew Clean, this product, also from Trac Ecological, worked slightly faster, and with slightly greater corrosion rates on the metal samples.
Bottom Line: Recommended for barnacles and heavy duty descaling.

[Tillsbury]

Converted from salt to fresh last year, will not go back. About to convert another.