Calling all chemists/limescale solution

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mocruising

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Having just had two new holding tanks valves and pipework fitted I would like to reduce the limescale build up. Old system lasted 12 years but when the pipes were removed they had been reduced to 50% of their original cross section area by lime scale. How can this be prevented mimimised in the future. What is the chemical process that causes lime scale as I never get it in any of the SW cooling pipes only the loo.
 
The only further explanation needed is the the 'muriatic acid' referred to in the link is dilute hydrochloric acid. In continental Europe it is available in every supermarket for exactly this purpose but less so in UK. 'Brick cleaner' is usually quoted as a source, available at builder's merchants.

I have never tried the vinegar method as HCl is so cheap in Europe, it's actually cheaper than drinking water in some shops. I would expect HCl to be far more effective.
 
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... ... I have never tried the vinegar method as HCl is so cheap in Europe, it's actually cheaper than drinking water in some shops. I would expect HCl to be far more effective... ...

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I have used white vinegar to clean heads parts and I would say that it's pretty useless. HCl is undoubtedly far more effective and I've used it to good effect to clean up a badly scaled calorifier.
 
My experience with using vinegar to clean lime scale is that it needs to be hot (or at least very warm) to work at any useful rate. Used in this fashion I have found it very effective. I worry about using brick acid as this is an extremely strong (though diluted) acid and I am not happy that I understand the consequences of applying it.

Regards,
Jeff.
 
Very many liveaboards dose toilets with HCl on a weekly basis. I've been doing mine like this for years, along with many others on these forums. No deterioration whatsoever.

There's nothing in the toilet that will suffer from this treatment. All seals, plastic parts and the ceramic are resistant to this acid. The acid reacts with the scale to produce calcium chloride, CO2 and water, so environmentally there is no big problem. I can't believe that the CO2 produced makes a significant contribution to the greenhouse effect /forums/images/graemlins/smile.gif
 
I agree about the reservations on using HCl. It's fine on plastic & neoprene but if you have metal skin fittings or with metal parts? One of mine looks as if it's zinc alloy and I'm not inclined to test its corrosion resistance!
 
In the original post you asked about the chemical reaction that causes scale. I don't think it is actually limescale but is calcite which is a much tougher compound.I asked about this some time ago and VicS was fairly helpful but not definitive.
I hoped that there was some simple additive that could be preventitive rather than remedial.
 
Calcite, limescale, both forms of calcium carbonate as are chalk, limestone and marble. Calcite is a crystalline form and at 3 on Moh's scale probably harder than what we would normally regard as limescale. I think I would prefer to reserve the name for the naturally occuring mineral.

Formed in the toilet plumbing I think because bacterial action on urea etc in the waste produces ammonia which raises the pH.

Remedial action would be based on neutralising the ammonia. Regular dosing with dilute acid would do this.
 
I would expect HCl to be far more effective.

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Brick and cement cleaner in B and Q is described as containing HCl Hydrochloric acid so should do well.
 
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I hoped that there was some simple additive that could be preventitive rather than remedial.

[/ QUOTE ]I'm one of the liveaboards Vyv refers to above as someone who doses the toilets every week with HCl. I don't think there is an issue with the seacocks -- I have not seen any evidence of it. My father used the same technique over 22 years with no problems.

However, I have also wondered whether there is any possible preventative. The best I can come up with is a small dose of weak acid on each flush, to counter the alkalinity of the ammonia formed by the breakdown of the urine. Or one could put some kind of preservative or antibacterial in with each flush to prevent the urine from breaking down (EDTA?) but the latter would be expensive and environmentally unacceptable, I think. A bottle of very dilute HCl sploshed into the bowl, with the sewage, before flushing, might work.
 
I can imagine weekly dosing helping keep the system clear but has anyone tried using HCl for the first time on a toilet system that is well clogged up - reduced by half as one poster comments? I can imagine it needing a lot of acid and a lot of time.
 
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I can imagine it needing a lot of acid

[/ QUOTE ] Yes. Concentrated hydrochloric acid is about 35% HCl so roughly 1 litre would dissolve 50g of scale.

Brick cleaners are somewhat more dilute. Half that at least and possibly very much less.
 
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I was thinking along the lines of these small dispensers you get in urinals which dispense a small amount of sweet smelling disinfectant with each flush. Could be worh a fortune!!!!

[/ QUOTE ]Yes, I've mused over that idea, too, as they are everywhere in Spain and Italy. I don't think you'd want to put HCl (even weak) in such a dispenser on a yacht and I suspect that only EDTA would work as an antibacterial in this application which would require large quantities. If you were to do it, you'd want a manual dosing system with a bottle on the wall and a bulb, with pump, to put some HCl in every time you pee. Could be done and I've thought about doing it but a fortune? How much would any forumite pay me for a working unit, in their hand including taxes and 12 month warranty? £10? £50? £100? I don't think that the numbers will crunch for most people. Anyway most people don't realise that there is a problem and when it arises they just change the pipes, so 80% of the market does not think it has a problem.

The answer is easy. For Jabscos... Every week fill to the brim with hot fresh water and add 1/2 litre of 5% HCl (e.g. Italy) or 1/4 litre of 10% HCl (Spain) don't know the strength of UK Brick Cleaner and pump out SLOWLY to the last 100cl. Then pour in a glug of old chip oil (or new, if you are a rich boat) and pump out -- do not flush for several hours. Do this every week. I don't know about other toilets -- I don't think it is very different but I don't know the materials and have no experience of them.
 
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Yes. Concentrated hydrochloric acid is about 35% HCl so roughly 1 litre would dissolve 50g of scale.

[/ QUOTE ]I don't doubt your numbers but in my experience, when I don't get around to doing a weekly descale loads of scale appears to fall back down the pipe after the next descale. You feel the 'grittiness' of scale in the piston. I suspect that 1g of descaling might result in 10g or even far more of scale dislocation, which then gets flushed-out. A couple of friends over the years have managed to clear their pipes by a few applications of HCl enough to get back in service and then do a descale every week.
 
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