Holding tank calcium deposits

As a slight diversion to this thread, is it practical to sue brick cleaner to dissolve the deposits in sea toilet pipes by, for example, flushihc a bowl of acide through the toilet with the sea cock open? Is there any chance of damage to the skin fittings?
 
birdseye said:
As a slight diversion to this thread, is it practical to sue brick cleaner to dissolve the deposits in sea toilet pipes by, for example, flushihc a bowl of acide through the toilet with the sea cock open? Is there any chance of damage to the skin fittings?
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I find it useful to flush HCl on a regular basis for preventive purposes but not to solve a blockage problem. When I tested brass, DZR and bronze seacocks by exposing them to a wide variety of household liquids, including HCl, I did not find a single one that even etched any of them in 30 minutes' exposure. Skin fittings and valves would only see the acid for a few seconds in the scenario you describe. The toilet itself, plastic, various grades of elastomer and stainless steel are all unaffected by HCl in a typical timescale of ten minutes until reaction stops.
 
Hydrozoan said:
Vyv and Vic, I'll concede that a 1000 fold rate difference or more is likely - my apologies for doubting that.
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No problems.
I am still wrestling with the logic in the Wikipedia article you quote. I dont have much appetite these days for the mental gymnastics involved so I think i'll let it go.
 
VicS said:
No problems.
I am still wrestling with the logic in the Wikipedia article you quote. I dont have much appetite these days for the mental gymnastics involved so I think i'll let it go.
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Thanks. No, I wasn't up to repeating the necessary calculations either - partly through other things being more urgent, and partly through a similar lack of appetite. I do think they've probably put the pKa in there, and if I ever summon up the enthusiasm for a thorough check I'll send you a PM with the outcome. But please don't hold your breath! :)
 
Some feedback to close this one off. I went for 5L of acid at €1.56 a litre from the local SuperU and the tank is spotless.

Thank you to all those who contributed.
 
So my question and purpose in resurrecting this thread is to ask about concentration of HCl.

Yesterday I finished off my supply bought in Croatian supermarket cleaning the NRV of the heads. All crud dissolved in about 15 minutes. Concentration was 11%. I used it neat! I need to stock up.

Now I am in Greece. Local supermarket has 5%HCl. Chandlery has 30% (!). I wonder if the 5% will do the trick - difficult to test now I have put the pipes back together! Or if I get the 30%, shall I dilute it? Do I remember correctly to add acid to water and not water to acid???

Thanks

TudorSailor (in Poros harbour)
 
To me it's just about the speed the HCI will remove the crud and the amount o crud it will remove with a given amount of HCI

The higher the concentration the faster it will work and the greater amount of crud it will remove for the same volume of HCI.

I use 30% HCI as that what is sold as swimming pool acid.
 
tudorsailor said:
So my question and purpose in resurrecting this thread is to ask about concentration of HCl.

Yesterday I finished off my supply bought in Croatian supermarket cleaning the NRV of the heads. All crud dissolved in about 15 minutes. Concentration was 11%. I used it neat! I need to stock up.

Now I am in Greece. Local supermarket has 5%HCl. Chandlery has 30% (!). I wonder if the 5% will do the trick - difficult to test now I have put the pipes back together! Or if I get the 30%, shall I dilute it? Do I remember correctly to add acid to water and not water to acid???

Thanks

TudorSailor (in Poros harbour)
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5 to 10% is probably what I would use depending upon the severity of the scale build up. 5% should shift light scaling but heavier scaling would take a little longer and might need a second go

30 % is getting on towards concentrated so would need a little more care with the handling and storing but yes dilute it to 5 to 10% to use

Yes generally add acid to the water. It's dangerous to to dilute concentrated sulfuric acid the "wrong" way. Hydrochloric acid is not so bad but concentrated HCl fumes like crazy if you do it the wrong way. 30% may not. Dunno always stated with the concentrated stuff ( about 36% IIRC)
 
I think it is about nomenclature. Until quite recently Greek HCl was sold as 30%, which I assume meant a 2:1 dilution of the concentrated acid solution. Recently it all seems to have become 5 or 6%, which is just the same stuff but now referring to the acid concentration in water. I have not noticed any difference in performance. I also doubt that Greek supermarkets would ever have sold concentrated hydrochloric acid.
 
So I bought some "30%" HCl from the Greek Chandlery. As soon as I took the lid off I appreciated that this is much stronger than the 11% sold in Italy and Croatia. The smell took me back to my A-level chemistry days.
I therefore have been super cautious in using this stuff and would much prefer to have 11% as I had previously.

TudorSailor
 
mcanderson said:
My holding tank has lumps of what I can only guess are lumps of calcium in the bottom. Sometimes the smaller of these get sucked into the pump which I use to empty the tank overboard. This results in me having to remove the lumps from the pump - not my favourite job. Any thoughts for how to break these up and then pump them away? I thought draining the tank and then adding 10l of vinegar.
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Try the following:~

Fill the tank with fresh water to one inch from the top and drop in a handful of Steradent Tablets (used to clean dentures) and see if that works....let us know the results.

I suggest it to you because that is how I keep the bowls in the heads sparklingly clean.

They have to remain overnight before flushing. The effect is astonishing.
 
VO5 said:
Try the following:~

Fill the tank with fresh water to one inch from the top and drop in a handful of Steradent Tablets (used to clean dentures) and see if that works....let us know the results.
Click to expand...

I don't think you will find that Steradent will be effective in removing a build up of magnesium or calcium carbonates. You will need something acid to do that. Steradent is almost pH neutral

Steradent contains peroxy compounds making it an effective stain remover.


tudorsailor said:
So I bought some "30%" HCl from the Greek Chandlery. As soon as I took the lid off I appreciated that this is much stronger than the 11% sold in Italy and Croatia. The smell took me back to my A-level chemistry days.
I therefore have been super cautious in using this stuff and would much prefer to have 11% as I had previously.

TudorSailor
Click to expand...

Dilute it 3 fold before using it if you prefer to handle a more dilute solution.
 
VicS said:
Dilute it 3 fold before using it if you prefer to handle a more dilute solution.
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I forget what they taught me at school. It was 60 years ago. :confused: But does one add water to the acid, or acid to the water. I think that it is acid to water , but I am not sure. However, being only 30% to start with I suppose it will not matter much.
 
VicS said:
Steradent contains peroxy compounds making it an effective stain remover.
Click to expand...
Steradent tablets certainly clean the bottom of the bowl if a couple of tablets are left in overnight in some water in the bowl.
Has the added plus that one can stick the wife' false teeth in there as well whilst doing it. :confused::D
Gives her the "Ring of confidence" in the morning. ;)
 
Daydream believer said:
I forget what they taught me at school. It was 60 years ago. :confused: But does one add water to the acid, or acid to the water. I think that it is acid to water , but I am not sure. However, being only 30% to start with I suppose it will not matter much.
Click to expand...
Acid to the water .............. but already stated in post #30
 
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