# How long can you store water?



## Ady34 (12 Jun 2012)

Hi,
after recent problems its got me thinking about keeping some pre prepared water ready for use in an emergency.
How long can you store tap water for before it goes 'bad'? 
I use 3x 25l drums to pre prepare my water change water the night before, dechloronate, add any conditioners and heat via 25w heaters to desired temp (or just sit in the house for unheated tank). How long would this water remain suitable for aquarium use without agitation/circulation and would it be better to seal or leave open?
Cheers,
Ady.


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## Aqua sobriquet (12 Jun 2012)

I'll have a guess and say without any additives it will store indefinitely provided it's in a sealed container excluding any air. With added chemicals it's hard to say though.


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## Iain Sutherland (12 Jun 2012)

Hey Ady, don't know how much help this is but the marine forum I use advise that RO can be kept for a week or 2 but once mixed with salt it should be used in 48hrs unless running an airstone and power head in it...Don't know the theory behind it.  Maybe similar with additives in tap???


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## Aqua sobriquet (12 Jun 2012)

Forgot to mention, light and temp are also considerations. It will keep longer if kept in a cool dark place.

I read many years ago that some marine fish keepers lucky enough to live near the sea would simply take sea water as far from the coast as they could manage then store it in a sealed bin bag inside a dustbin in a cool place. Kept like this for several weeks was reckoned to kill most stuff likely to cause harm and could then be put into the aquarium once up to temperature.


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## Ady34 (12 Jun 2012)

Thanks for the replies guys. Maybe best to keep a store of untreated tap water for upto a week or so in a sealed drum in the garage, and add conditioners and heat when necessary. I suppose a kettle or two of boiling water would help warm it up in an emergency! I suppose if i was really stuck i could mix hot and cold straight from the tap (combi boiler) and condition on the spot to add to the tank.
Cheers,
Ady.


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## Christie_ZXR (13 Jun 2012)

Personally, I make up a ton of RO about once every 3 weeks or so, and it seems to keep well for that length of time in my odd collection of bottles and tubs.


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## Nathaniel Whiteside (13 Jun 2012)

Christie_ZXR said:
			
		

> Personally, I make up a ton of RO about once every 3 weeks or so, and it seems to keep well for that length of time in my odd collection of bottles and tubs.



Same as me, leave 25L RO tubs for weeks at a time. Have one in house at room temp and one in shed.

Regards


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## dw1305 (14 Jun 2012)

Hi all,


> Personally, I make up a ton of RO about once every 3 weeks or so, and it seems to keep well for that length of time in my odd collection of bottles and tubs......Same as me, leave 25L RO tubs for weeks at a time. Have one in house at room temp and one in shed.


This is true, RO keeps for ever in a sealed container it is H2O and will remain H2O for all of eternity. Even unsealed the amount of pollutants it will pick up from the air is negligible. Same applies to any low nutrient  water (like rain-water), you can store it indefinitely.

cheers Darrel


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## sr20det (14 Jun 2012)

dw1305 said:
			
		

> Hi all,
> 
> 
> > Personally, I make up a ton of RO about once every 3 weeks or so, and it seems to keep well for that length of time in my odd collection of bottles and tubs......Same as me, leave 25L RO tubs for weeks at a time. Have one in house at room temp and one in shed.
> ...



Whats about tap water?


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## ian_m (14 Jun 2012)

dw1305 said:
			
		

> .... RO keeps for ever in a sealed container it is H2O and will remain H2O for all of eternity.....


Not quite pedantically true    
The proton has a 1/2 life estimated 6.6 x 10^33 years, thus water will not last for all of eternity.

http://en.wikipedia.org/wiki/Proton_decay


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## dw1305 (14 Jun 2012)

Hi all,


> What about tap water?


 It shouldn't change much in composition, although you may get some precipitates. The main problem is that it will grow algae, and bacteria will multiply once the residual chlorine has out-gassed. As you aren't going to drink it, if you have it in a light-proof container it should be fine, although you will probably only need to store it for a few days at most until it is at room temperature. 

If it was a case of getting 100 litres of tap water from a friend in mid-Wales, and then using to change your water over the next few weeks in London etc., I wouldn't see any problem.

If you get any light above compensation point, even with almost pure water, a fuzz of green algae will develop on the container sides. Again this doesn't affect water quality, but it is almost impossible to get rid of.

cheers Darrel


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## dw1305 (14 Jun 2012)

Hi all,


> The proton has a 1/2 life estimated 6.6 x 10^33 years, thus water will not last for all of eternity


 OK, I'll reserve us a table in the "Restaurant at the end of the Universe" in 660,000,000,000,000,000,000,000,000,000,000,000,000 years time for June 15th at 19:30, table in the window. Unfortunately looks like "soup of the day" will be off the menu.

Darrel


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## Nathaniel Whiteside (14 Jun 2012)

dw1305 said:
			
		

> Hi all,
> 
> 
> > The proton has a 1/2 life estimated 6.6 x 10^33 years, thus water will not last for all of eternity
> ...



I'd probably have developed wrinkles by then..


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## Ady34 (14 Jun 2012)

dw1305 said:
			
		

> Hi all,
> 
> 
> > The proton has a 1/2 life estimated 6.6 x 10^33 years, thus water will not last for all of eternity
> ...


  


			
				dw1305 said:
			
		

> This is true, RO keeps for ever in a sealed container it is H2O and will remain H2O for all of eternity. Even unsealed the amount of pollutants it will pick up from the air is negligible. Same applies to any low nutrient water (like rain-water), you can store it indefinitely.


My tap water has a TDS of 76ppm, does this effectively mean it contains less of anything (much like RO, or rain water) that could cause a potential issue, or is it more to do with chlorine etc?
Would a water report show concentrations of any nutrients which could cause issue?
Cheers,
Ady.


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## dw1305 (14 Jun 2012)

Hi all,


> My tap water has a TDS of 76ppm, does this effectively mean it contains less of anything (much like RO, or rain water) that could cause a potential issue......?


 Yes pretty much. Any chlorine will out-gas naturally fairly quickly. The only thing worth looking for on the water company report would be nitrates, although my suspicion would be that they will be fairly low. High nitrates isn't a problem, it just means you would end up with more algae on the walls of your storage container if it was in the light.

Our tap water in Corsham is about 400ppm TDS, but this is nearly all calcium carbonate hardness. The water must come from a deep limestone aquifer and is much better quality than most bottled spring water.

cheers Darrel


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## sr20det (14 Jun 2012)

dw1305 said:
			
		

> Hi all,
> 
> 
> > My tap water has a TDS of 76ppm, does this effectively mean it contains less of anything (much like RO, or rain water) that could cause a potential issue......?
> ...



If stored in dark? Cool places?


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## dw1305 (14 Jun 2012)

Hi all,


> If stored in dark? Cool places?


 Yes ideally to both, but dark will do.

cheers Darrel


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## Archie (18 Jun 2012)

Interesting subject. Regarding chlorine out-gassing, roughly how long does that take? I store tap water in plastic milk bottles in a cupboard for a week before water changes. I do that on the assumption that after 7 days it'll be room temperature (obviously) and dechlorinated, is that right?


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## dw1305 (18 Jun 2012)

Hi all,


> I do that on the assumption that after 7 days it'll be room temperature (obviously) and dechlorinated, is that right?


 Yes. 





> I store tap water in plastic milk bottles in a cupboard for a week before water changes.


 So do I, 6 pint milk carton is the best freebie ever invented.

Chlorine is a bit of a strange element, the chlorine ion dissolved in water is as hypochlorite 2(ClO-), the same ion as in sodium hypochlorite (NaCl2O2) bleach (with an Na+ ion). The break down reaction is actually quicker in the light, but if the bottles aren't really full (reducing the surface area) 24 hours should be plenty. Sodium hypochlorite remains dissolved in the water supply only as long as the water is under pressure, as soon as the water is released from your tap the chlorine rapidly diffuses into the air along its concentration gradient, in just the same way that added CO2 would.

cheers Darrel


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## Ady34 (18 Jun 2012)

Does that mean im wasting my money on chlorine and chloromine remover when im leaving my water overnight (24hrs) before adding to my tank, or am i best off continuing to add it just incase?
Thanks,
Ady.


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## Aqua sobriquet (18 Jun 2012)

If the water is stored in a sealed container does the chlorine stay in solution then?


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## sr20det (18 Jun 2012)

Ady34 said:
			
		

> Does that mean im wasting my money on chlorine and chloromine remover when im leaving my water overnight (24hrs) before adding to my tank, or am i best off continuing to add it just incase?
> Thanks,
> Ady.



I do the same purely to get water to room temp. Interested to know also.


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## ian_m (19 Jun 2012)

Ady34 said:
			
		

> Does that mean im wasting my money on chlorine and chloromine remover when im leaving my water overnight (24hrs) before adding to my tank, or am i best off continuing to add it just incase?
> Thanks,
> Ady.


Nope not wasting money as often water the treatment you add to your water also "takes out" heavy metals that might be present in the water (copper etc), as well a chlorine and chloramine.

Years ago (maybe 20 odd), before Prime etc people used to either bubble an airstone through their stored water for 24hour before using or make their own dechlorinator using Hypo (sodium thiosulfate) from photographic shops (its fixer I think).

More here.http://www.skepticalaquarist.com/chlorine-chloramine


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## Ady34 (19 Jun 2012)

ian_m said:
			
		

> Ady34 said:
> 
> 
> 
> ...


Thanks for that, ill keep adding the water treatment.


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## dw1305 (20 Jun 2012)

Hi all,
Yes, "hypo" is the fixer that reacts with the silver bromide in B/W photography. 





> http://www.skepticalaquarist.com/chlorine-chloramine


 Is well worth a read.


> If the water is stored in a sealed container does the chlorine stay in solution then?


 No, it is an efficient disinfectant because it is a very strong oxidizing agent. This means that it forms compounds very easily and will react with any cations like sodium (Na+) or calcium (Ca++) to form sodium chloride (NaCl), calcium chloride (CaCl2), as well as any organic matter to form organochlorines like chloromethane etc. 

Sodium thiosulphate (Na2S2O3•5H2O,) de-chlorinaters work by producing NaCl as well. 
(As well as other compounds ~ 2Na2S2O3   +   HOCl   >  Na2S4O6    +  NaCl +    NaOH)  

Chloramines are slightly different, chloramine has a much longer half life in the tap water. The reason chloramines persist is due to their lower oxidative (redox) potential.  They degrade to chlorine and ammonia (NH3/NH4+) relatively slowly, meaning that extra ammonia (and chlorine) is constantly added to the tank water. 

A conditioner like "Amquel" or "Prime" contains sodium hydroxymethanesulphonate, as well as sodium thiosulphate, and works by combining the free ammonia into larger, more complex, molecules like H2NCH2SO3Na, a sodium aminomethanesulphonate salt.

You can actually ignore any potential heavy metal poisoning, the EU regulations are really tight, and all the water companies are adding sodium hydroxide (NaOH) and orthophosphate (PO4---) to remove the chance of any copper (Cu) or lead (Pb) ending up in solution.

cheers Darrel


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