Calcium Carbonate (limestone) in looping toilet outflow

[aberglas]

My electric seawater flush toilet outflow has blocked with rock again because crew do not flush it properly. Urine + Seawater = rock.


Diluted hydrochloric acid converts it to CO2 nicely (vinegar is useless).


However, the boat has a long exit pipe that loops high above the toilet and then down to the through hull fitting under the waterline. The top of the toilet is only a foot above the waterline. I think this is to prevent back flow. There is no siphon break, but I think flushing would introduce some air into it once the bowl is empty.


Trouble is that the acid creates CO2 which pushes the acid out of the boat without letting it do its job on the downward part of the pipe. I put an eel though it from the outside, but did not fully clear it.



There is a one way rubber valve on the TMC toilet, good condition but asking a lot for a permanent seal.



I am considering shortening the out pipe, just go straight out and forget the loop.


Thoughts?

[Pete7]

Without the loop the discharge hose will reverse the flow and the heads will spill out the top all over the compartment and eventually sink the boat if you are not on board. So the loop is essential.

Stop messing about with alchemy and just replace the hose.

Pete

[Fore and Aft]

Aberglas we easily got six years out of our last toilet hoses before I decided to replace them. The inside of them was clean as and I can only attribute that to using toilet duck at least once a week. I give the bowl a liberal dose and flush the toilet until the bowl is foamy. It seems to work wonders on the plastic holding tank as well. I expected it be stinky when I replaced the hoses. But the odor was fine.
You can also have a timer on your flush button so once touched the toilet keeps flushing for a minute or two. Lots of charter boats have that.
Cheers

[peghall]

There should be a vented loop (siphon break) in any line connected to a below-waterline thru-hull. The hydrochloric acid (aka "muriatic" acid, available from most hardware stores) should sit in the hose for 45-60 minutes to accomplish anything, then be followed by a fresh water rinse. Closing the seacock before using it will accomplish this.


The one-way rubber valve in the toilet discharge fitting is called a "joker" valve (I have no idea why)...joker valves are not permanent...they stretch with use and should be replaced at least annually. They can also become encrusted with sea water minerals (not urine crystals, so increasing flush water won't prevent it ) that also build up in the toilet discharge line, reducing its diameter. Hydrochloric/muriatic acid when used correctly is the cure for this. Although vinegar won't dissolve it (it will, but it's too labor intensive (must be replaced hourly) an undiluted cupful of distilled white vinegar flushed through the toilet weekly will prevent it.


--Peggie

[SailingHarmonie]

The deposits are actually mostly calcium oxalate (like a kidney stone) than "limestone" and a 5% solution of phosphoric acid will be just as effective at dissolving it as hydrochloric acid, and be MUCH gentler on the metal parts of your system.

If you really think vinegar will ever work, take a chunk of this stuff and drop it in a gallon of straight up undiluted vinegar. Stir as much as you like. Watch nothing at all happen for hours and hours...

[peghall]

Vinegar does work to PREVENT buildup when used at least weekly because the layer is so thin that vinegar can dissolve it as it passes through. Vinegar CAN remove a buildup but you, like most people, have never learned that it "exhausts itself" in about an hour (which is the reason it can sit in the hose for a week without doing anything...it's done all it can in the first hour.) and so must be replaced hourly ..making it way too labor intensive to be worth the effort when muriatic acid does the job so easily.


--Peggie

[sailorboy1]

Best way to use vinegar in the head is to put a squeeze bottle next to to the head and give it a shot EACH use.

After 15 years of chemical treatment I can say is it WAY easier to prevent scale than to remove it.

I can also say wit experience that even a fresh water flush head can scale the hose if the cit water is very hard (like Jacksonville FL)

[peghall]

And all of the ways to descale sanitation plumbing today beats the socks off removing it section by section to take it off the boat and beat it on the dock to dislodge all the buildup in it, then re-install it, which most sailors once considered the ONLY way to do it.


--Peggie

[GordMay]

Originally Posted by sailorboy1

... I can say is it WAY easier to prevent scale than to remove it...

Indeed!
In any situation, prevention is always better than cure.

The phrase: 'prevention is better than cure' is often attributed to the Dutch philosopher, Desiderius Erasmus, in around 1500.

[DominoX]

What concentration of vinegar are you folks using?.

I’ve used regular off-the-shelf stuff from grocery stores for years (which is about 6%), with little effect.

I also got 95% vinegar in a gallon from Amazon, and used it undiluted. Again, I didn’t notice a meaningful difference.

What’s your opinion on the minimum concentration needed to be effective?

[peghall]

To repeat what I said in post #6: There is no concentration of vinegar that will work unless it's replaced hourly, because that's how quickly even undiluted vinegar exhausts its ability to accomplish anything. That makes vinegar too labor intensive to be worth using when muriatic/hydrochloric acid does the job in an hour unless the buildup is so thick that it requires more than one "dose."



--Peggie

[CarinaPDX]

I have used vinegar to clean mineral buildup from bronze plumbing parts. As Peggie says, the reaction doesn't last long and the vinegar must be constantly replaced but it does work and is relatively safe. I believe that vinegar, which is the name for ascetic acid used in foods, has a standard strength which is a limiting factor.

I wish to warn cruisers about muriatic acid. Muriatic acid is a diluted form of hydrochloric acid, which when concentrated is a very strong acid. The muriatic acid that I bought in Europe was much more dilute than the US form. The European version was great for cleaning heads and hoses, with due caution being practiced. The US version is dangerously strong and must be used with care. It can cause serious burns: gloves and eye protection are a necessity.

Greg

[peghall]

It's rarely use full strength...a 12-15% dilution is common.


--Peggie

[LeGe]

Originally Posted by Pete7

Without the loop the discharge hose will reverse the flow and the heads will spill out the top all over the compartment and eventually sink the boat if you are not on board. So the loop is essential.

Stop messing about with alchemy and just replace the hose.

Pete

Definitely the best idea. It’s not a pleasant job but not that hard either. Just need a little resistance to pain to get it through the bulkhead to the waste water tank.

[CarlF]

If you have a watermaker aboard, convert to fresh water flush. Everything smells better, head parts and joker valves last longer, and an end to hose blockages.