Where does the lime scale in the loo come from

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mithril

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OK probably an old topic but where exactly does it come from? Is it,

a) From the seawater, if so why is my hull not 25 mm thick with lime scale, and why is the inlet pipe for water to flush the loo still clear? /forums/images/graemlins/confused.gif

b) From the fresh water I p—s down the loo, if so why do my fresh water pipes to the galley remain clear? /forums/images/graemlins/confused.gif

c) That the body actually adds something to the fresh water to make p—s and so make it lime or calcium rich and hence fur up the pipes?
/forums/images/graemlins/frown.gif
 
The average healthy adult voids up to 250 mg per day of Calcium through peeing.
I believe there is some reaction with salt water that causes it to crystalize out.
Hopefully Peggy Hall knows the finer points and will fill us in.
So the answer is yes - it is your body ( and others !!) that limes up your bog.
And there is nothing you can do - if your Calcium excretion level falls below 100 mg per day you will be very ill ...

Hope this helps..

BTW Coca cola is a very good descaler for the heads - I'm glad it has some use...
 
Can't answer your question but I stripped out our baby blake today and the outlet pipe (1.5 inch) had only half the bore the left to flush with. This is after around 10 years so accounts for the thing starting to struggle to flush which is why it is out. I must admit that I do have a go at the people who do not flush it well as it starts to smell ....
 
"OK probably an old topic but where exactly does it come from?"

It's not your body...nor is the waste...it's the sea water.

What you're calling lime scale is actually sea water calcium carbonates, which thrive in anaerobic (oxygen starved) environments (hoses)...which explains why they don't also build up on your hull...the outside of the boat gets all the oxygen it needs. They're always present in sea water...they just need the ideal environmnent (anaerobic = without oxygen) in which to thrive. They're a lot less of a problem in cold waters than in warm waters, 'cuz the salt/mineral content of warm sea water is a lot lower than in cold sea water.

White vinegar does a wonderful job of dissolving 'em....so if you want to eliminate 'em in your hoses, put a cupful--no more...more will just be flushed through and therefore wasted--of white vinegar through the lines once a week.

If you have serious buildup, a 12% solution of muriatic (or whatever you Brits call it) acid in water (read and follow ALL the directions for handling and mixing!!!) will do it...then, once you've cleared out the line, keep it clear with a cupful of white vinegan once a week.
 
Hi Peggie,

Not really breakfast reading, but thanks, that's so simply explained even I understand it! /forums/images/graemlins/smile.gif

You've mentioned white vinegar before, but what I don't understand, is that if for example, I put a cup of water down the pan of my Lavac and pump with the lid open, air is drawn in almost immediately. Only what appears to be a small amount disappears, certainly not enough to 'fill' the pipework, which in our case is only 7 feet long.

Is it the fumes from white vinegar (I haven't tried this yet) that do the job, or should I be pumping seawater/freshwater through in the normal way? And roughly how many pumps should be needed as I wouldn't want to flush the vinegar out completely? /forums/images/graemlins/confused.gif

When cruising (and not having the benefit of your advice) I remove the pipe each year and 'bang it out' on the dockside. This shifts all the build up but is real pain to do!! An easier solution would be excellent!! /forums/images/graemlins/smile.gif

Thanks Jerry
 
Thanks for all of the replies particularly Peggie the Headmistress.

Regarding white vinegar, I think its what the EU bureaucrats call non brewed malt condiment but without the malt. Its acetic acid. /forums/images/graemlins/smile.gif
 
Hi!

Yep, I remember it basically being acetic acid from my school days!! It's how you get it to 'stay' on the pipe walls to do its job that baffles me!

I hope Peggie or someone else can explain that. A cupful seems so little!
 
I was wrong !!!
Thank you Peggie....

So what happens to the 250mg / day contribution from our bodies ?
Does it not add to the scaling effect ? or is it the "wrong" type of calcium ?
 
[ QUOTE ]
Regarding white vinegar, I think its what the EU bureaucrats call non brewed malt condiment but without the malt. Its acetic acid. /forums/images/graemlins/smile.gif

[/ QUOTE ]

Or simply, white wine vinegar.
 
[ QUOTE ]
If you have serious buildup, a 12% solution of muriatic (or whatever you Brits call it) acid in water

[/ QUOTE ] Hydrochloric acid!
 
Flush undiluted white vinegar last thing before the boat will sit--or at least when the head won't be used for several hours..enough of it is absorbed by the minute mineral particles in the hose as it passes through to dissolve 'em before they can build up. Flush it all the way through the hoses...if you have a y-valve, flush a cupful through one side, a second cupful through the other side. No need to use any more...more will only be flushed out...wasted.

Do NOT leave vinegar sitting in the bowl! For one thing, it won't do any good for the hoses there...for another, it will seep into the discharge leaving the joker valve to soak in it. Vinegar just passing through the joker valve or the rubber bits in the pump won't hurt 'em...but when soft rubber is left to soak in vinegar, it swells and distorts.

White (clear distilled) vinegar is more acidic than cider vinegar--I THINK because it's distilled more completely (I'm gonna have to look that up one of these days), so it's more effective.

Jerry said, "it's how you get to stay on the pipe walls that baffles me."

The same way that water droplets stay on pipe walls...the inside of the hoses isn't immediately dry after a flush with water...they aren't after a flush with vinegar...it "wets" the inside of the hoses, same as water does.

Does waste contribute to the buildup? Yes...however, the calcium we excrete and sea water calcium carbonates are two different things. Salt and sea water minerals make the inside of the hose increasingly rough....anything passing over a rough surface will leave a little behind...which traps more salt and minerals...which trap more waste. Buildup isn't a problem in systems that flush using fresh water.

Btw...if you use bleach or a chlorine tablet in your intake (which is a bad idea anyway because chlorine is highly destructive to rubber and hoses), make extra certain that your toilet is in the dry mode before flushing vinegar (which it should be anyway, to prevent diluuting it)...the combination of vinegar and chlorine makes an even more lethal gas than chlorine and ammonia.
 
Hi Peggie!

That's terrific! Thank you very much for that, it makes it extremely clear. I'll add it to my 'leaving the boat' routine right away.

Thanks again

Jerry
 
Sea water is saturated with Calcioum bicarbonate which is formed by carbon dioxide and insoluble calcium carbonate.
Carbon dioxide dissolves in water forming a weak acid which dissolves the calcium carbonate.
Urine is slightly alkaline when produced but is attacked by microorganisms to produce ammonia which is much more strongly alkaline.
The alkaline ammonia solution reacts with the calcium bicarbonate to produce calcium carbonate again which is insoluble and forms the scale.
I agree that a lot of flushing will get rid of the urine before it has much chance to decay to ammonia.
Incidentally the carbonate / bicarbonate cycle without ammonia is what dissolves holes in limestone and produces stalactites etc. but rather more slowly than blocking up head pipes.
 
Re: Sea Salt

On another topic, re sea water, anyone know what's so special or different about 'sea salt' compared with mined salt (from Cheshire in UK) since this latter must have been sea salt originally.
It's just the way cooks rave about 'sea salt' as if its a different sodium chloride.
 
Re: Sea Salt

Sea salt is not pure NaCl,it is the crystal result of evaporating sea water and therefore has loads of impurities in it which the cognoscenti would have you believe adds appreciably to the flavour.There may be some dietary benefits because of these impurities,trace elements etc.
As my taste buds have been permanently blunted by smoking and alcohol I can't tell the difference!
 
Agreed a good, brief, explanation but for one thing. Urine is initially slightly acidic. Test yourself with some pH paper if you dont believe me. Ammonia is produced by the action of certain bacteria on the urea in it.
 
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