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How to store RO water

OwenJ

New Member
Joined
8 Apr 2024
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7
Location
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I was planning on buying my reverse osmosis water from my LFS as it was relatively cheap as I only need about 10L a month. However, I was wondering how long you can keep a container of RO water until it goes bad as I was planning on filling up the container monthly.
 
I use rainwater from a 400ltr water butt. It’s often more than 4 weeks old, so I think you’ll be fine with 1 month old RO.
 
I was planning on buying my reverse osmosis water from my LFS as it was relatively cheap as I only need about 10L a month. However, I was wondering how long you can keep a container of RO water until it goes bad as I was planning on filling up the container monthly.
Stored in a dark place, it shouldn’t go bad in sealed containers.
 
What does goes bad actually mean in this case? Leaching from the container? What is left in RO water that can spring into life or is it just from filling to non sterile containers? I'm always amused by bottled water that says something like 'filtered naturally through rocks over hundreds of years, use before 3 weeks'
 
As said, just keep it in a dark place or use a black container. My rainwater often has a pretty *low TDS but it will still go green if it’s not stored carefully.
* I collected some overflow direct from the shed gutter during a heavy downpour and the TDS was around 2-3.
 
Imho It’s dependent on what you are storing it in
Glass is best
Potable water Container next
Most plastics leach phthalates
phthalates help make plastic flexible and durable
They are harmful to the endocrine system, with potential subsequent organ failure, the levels required to cause this are high, phthalates also break down fairly quickly, so drinking from plastic containers is extremely unlikely to be a problem to us human's, however I think it’s worth bearing in mind when storing water for our fish
Personally I don’t use cling film to wrap food, perhaps I am being over cautious
I use an old aquarium to store RO water
 
years ago at uni, I worked alongside an analytical group
They had been asked to analyse a sample for I don’t know what, the samples arrived in plastic containers
I don’t recall the method being used, all I recall is that the analyte signal was swamped by massive signal from an (initially) unknown compound
When the samples were resent, this time in glass containers, the job was successfully carried out
It was at this time that I “discovered” phthalates
 
I have one of these in the loft in case we get advanced notice of an interruption of supply. No idea if it’s any safer than the other plastic water containers I have in various sizes I use for the fish tanks?

IMG_9934.jpeg
 
I have stored mine in food-grade Jerry Cans and have had no problems with storing/using RO water for 6 weeks. They are stored in a dark place and the Jerry Can is airtight.
 
Imho It’s dependent on what you are storing it in
Glass is best
Potable water Container next
Most plastics leach phthalates
phthalates help make plastic flexible and durable
They are harmful to the endocrine system, with potential subsequent organ failure, the levels required to cause this are high, phthalates also break down fairly quickly, so drinking from plastic containers is extremely unlikely to be a problem to us human's, however I think it’s worth bearing in mind when storing water for our fish
Personally I don’t use cling film to wrap food, perhaps I am being over cautious
I use an old aquarium to store RO water

One thing to be aware of with distilled or RO water when storing it is that if exposed to air it will rapidly suck up CO2 and produce H2CO3 (carbonic acid) thus drop the pH considerably which could cause a reaction with the material of the container and release unwanted compounds (often toxins) - if the container shows signs of deterioration that would be a red flag. In general, I wouldn't worry too much about storing RO water long term if it's in an air tight container certified for storing drinking water (outdoors/camping stores sell those). And of course, not exposed to direct sunlight, spent fuel rods from a nuclear power plant etc.

Cheers,
Michael
 
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I been storing ro in Jerry cans 2 months at a time with no problems for like forever. Folks in the marine hobby store ro in huge plastic containers for many more months and keep the most delicate of corals.
 
A month should not be a problem ,some people use an air stone, I don't personally.
 

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