Filling water tanks?

[VicS]

[ QUOTE ]
sodium metabisulphate

[/ QUOTE ] Sodium metabisul<u>phite</u> , Campden tablets

The "fumes" are sulphur dioxide. SO2 is very soluble in water so should be relatively easy to "wash out" . For best effect the solution of metabisulphite can be slightly acidified with a few crystals of citric acid, that will release more SO2.

In terms of toxicity chlorine is more toxic with an occupational exposure limit (8hr TWA) of 1 ppm compared with 2ppm for SO2

 

[jon]

Nobody has mentioned water filters. I would use tabs or Milton on a regular basis and use a filter at the drinking water supply. Completely removes any tainting, but if the boat is not used regularly,then flush through well before use and change the cartridge annually.

 

[Bejasus]

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Nobody has mentioned water filters.

[/ QUOTE ]

see my post above.

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Normally for drinking water I use a Seagull IV filter unit which is the best there is.imho'

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[jerryat]

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Nobody has mentioned water filters. I would use tabs or Milton on a regular basis and use a filter at the drinking water supply.

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Yes, we also have a filter fitted to one tap only, in our case the galley. This means that the filters last much longer than if the water to the heads/shower etc went (unnecessarily) through it too.

 

[huldah]

Oops, am I missing something? I have never cleaned my tanks, or treated the water.

I drain my tank each winter, and then refill with fresh, untreated, local spring water. It is tested for purity and being free, is very economical. It makes a fine cup of tea!

Philip

 

[VicS]

[ QUOTE ]
Oops, am I missing something?

[/ QUOTE ] Just the foul taste of tea made with water containing chlorine, sulphur dioxide and hydroden peroxide! /forums/images/graemlins/laugh.gif

 

[jimbaerselman]

Clorox, Bleach without surfactants and Milton are all solutions of Sodium Hypochlorite. The only difference is the concentration of the solutions. From memory, we're talking around 7% for chlorox and bleach, and decimals of a percent for Milton (which, due to successful marketing, costs many times more).

None of these will affect stainless steel. All release free chlorine ions, a highly effective biocide. If you can just smell chlorine in your water, the bugs are bieng killed. A typical solution for a serious de-bugging is 1% of bleach or chlorox (about 10% of Milton!) so I know which I'd choose.

If you wish to get rid of the smell of chlorine more quickly than by repeated flushing, send a 1% solution of vinegar through the system. That'll flush out all the chlorine ions.

Tabs, silver ion release agents and other proprietry
water purification systems are good to maintain a clean system, but sometimes expensive to clear out a poluted system.

Happy flushing.

 

[VicS]

[ QUOTE ]
From memory, we're talking around 7% for chlorox and bleach, and decimals of a percent for Milton

[/ QUOTE ] Not a good idea to rely on memory. The concentration of hypochlorite may well vary in different products but Domestos is < 5% according to the label. It is certainly lower in Milton but nothing like as low as you suggest. Definitely not lower than 1%, but as the bottle is on the boat I will not attempt to remember precisely what.

[ QUOTE ]
A typical solution for a serious de-bugging is 1% of bleach or chlorox (about 10% of Milton!) so I know which I'd choose

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The recommended dose of Chlorox for treating drinking water is 1/2 teaspoon per gallon which, assuming a US gallon and a 5ml teaspoon, is only about 0.07%. IIRC the dose rate recommended for Milton is 2.5ml per 5 litres. That's only 0.05% and vastly different to the 10% you are suggesting.
At those concentrations there is no discernable chlorine residual after standing for a while.
There is no reason to suppose that domestic bleach will be made from anything other than a commercial grade of hypochlorite which can contain chlorate (as in weed killer!) as an impurity. Hopefully Milton does not contain chlorate, in fact it contains about as much sodium chloride as it does sodium hypochlorite which I believe prevents the formation of chlorate.

As I can afford the £1.74 or so for a bottle of Milton and prefer not to dose my drinking water with weed killer I know which I will be using.

I would consider additive free domestic bleach for a seriously contaminated tank at 1 or 2%, partly because of the volume required to treat a decent sized tank. I would flush the tank thoroughly afterwards.

 

[jimbaerselman]

VicS,

Thanks for the corrections re Milton.

What I should also have made clear is that I was talking about concentrations for flushing a contaminated system ('de-bugging', my imprecise words!), as apart from the concentrations for water treatment - the point you make at the end of your post.