Chlorine Storage Temperature (Heat) Impact


May 5, 2019
Scottsdale, AZ
What is the exact impact of various degrees of temperature (heat) on chlorine storage?

Hey Folks,
I'm looking for a more detailed technical answer for the above question other than the generic "store in a cool, dark, well ventilated place". I would like to know what the exact impact that heat has on chlorine within normal environmental ranges, say a range of 100 degrees (shaded & vented cool box) to a max of 200-220 degrees as an extreme (rubbermaid container accidentally left in sun). I live in the Phoenix, AZ area and quite frankly, the "store in a cool, dark, well ventilated place" doesn't really exist here so I would like to know the fundamental chemistry impact on chlorine (liquid 10%-12%, tri-chlor, di-chlor, cal-hypo) so I can keep that in mind for various options/solutions for storage (indoor & outdoor) and automated dispenser designs/solutions.
Since searching for this gets significantly diluted by discussion on "how much chlorine to use when it gets warm out", I've found it difficult to research this on my own Google-Fu skills. I did go through the following thread but much of it was just personal testimony of "seemed OK to me". Storing Liquid Chlorine
I'm hoping in this section someone can provide a more detailed and technical explanation.

I am well versed in the impact of sunlight (ultraviolet) on Chlorine (this is Arizona after all) but details on "why a cool location for storage" seems to be lacking (other than "well, that's what the manufacturer says to do").
I'm also fairly familiar with the chemical impact on the surrounding environment (like that chlorine fumes can corrode metal nearby).

If in a shaded (dark) and well ventilated area, does ambient environmental heat make any actual impact under 220'F? 140'F?

Thanks everyone!


May 5, 2019
Scottsdale, AZ
Thank you both, that is a great reference resource for the temp/time breakdown!

Though, that's a bit surprising and shocking to be honest. The most new plain pool liquid chlorine I have ever seen in a store is over a month old on the pallet (often 2-3 months old once it gets to the shelf) and from what I've seen from local distribution points (Leslie Pools, Ace Hardware, Home Depot, Walmart, etc.) they don't seem to store/ship it locally in climate control (it's almost always "warm" when the pallet is new on the sale floor/shelf).
According to these tables, it would be virtually impossible to get 10% from a retail location (let alone anything higher). Even a container marked 12% would likely be more like a 9.5% at best (or even much lower in less ideal shipping/storing).

This likely explains a LOT of why my pool is anything but trouble free: needing almost daily testing/attention and always needs more chemicals than estimated. (forget going out of town for a week without making it nuclear first)
After years to educating myself and stabilizing every possible test I could, I just chalked it up to poor design of the pool (bad water circulation perhaps). But now knowing that a fundamental expectation I've had of the chlorine might not actually be true, that makes me rethink my entire approach.

I see both of you are using SWG. I might have to take that consideration more serious (or maybe a cal-hypo micro-tablet chlorinator).


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
Most liquid chlorine is bottled at a higher concentration than labeled. So as long as you do not buy really old stock or store it too long in high temperatures, it should be relatively close to the labeled concentration.

It appears you have committed to adding liquid chlorine daily to maintain your pool water chemistry. And daily means daily in the summer. To go away for a few days, you can use trichlor in a floater. Or to really makes things far easier, get a SWCG.
  • Like
Reactions: Tonic1080