Refrigerating bleach/liquid chlorine to extend its life?

[y_not]

I was wondering if I can refrigerate the sodium hypochlorite I use for my pool.
Say 10-12.5% concentration and maybe even the 8.25% if I have some left over once winter hits.
Just for the purpose of slowing the breakdown process and prolonging its life at X concentration.

I have a junk fridge in the garage that keeps non critical things cool enough. So if it corrodes some exposed metal part somewhere inside, behind the visible walls and out of the way. I could care less.
My only concern would be the CL gas building up inside from the cap vent and if that's going to be a problem. IE. Flammable.

Thoughts?

 

[woodyp]

Why bother? You can easily keep a month or so supply on hand-------even in Texas!

 

[chem geek]

It probably isn't worth it for lower concentration bleach, but for higher concentration chlorinating liquid it would be OK though it doesn't have to be that cold. See the table at the bottom of this link where you will notice that the degradation is pretty slow even at 75ºF. There's roughly a doubling of half-life for every 10ºF drop in temperature. If you have a cool garage in the winter at 60ºF or 50ºF, that should be plenty. A refrigerator is usually at 38ºF or a bit below (but above freezing). At the low temperature of the refrigerator, the chlorine will not only degrade very slowly, but shouldn't outgas very much either.

 

[y_not]

Why bother? You can easily keep a month or so supply on hand-------even in Texas!

Well, we don't go through it as fast here in Oregon. It's not as consistently hot as it is in Tejas, it does get that hot sometimes, but it doesn't stay for long. Maybe a few weeks for +100F weather. Even then it's usually just the high 90's. But the sun here is a scorcher!! Don't let those seemingly low temps fool ya. We're at 3,500ft elevation with super clear atmosphere. So high UV /w that "baking" effect, furnace blast feel on the skin.

So it has to sit around a lot longer, the pool is smaller (for now) so I go through it slower & I bought it before the season started, really a month or 2 before hand.
In fact, we're just now getting the pool setup for the season. It has only just been consistently warm enough to bother. Had a week of 38-40deg overnight lows last week, but some days hitting 98deg F!
It's very, very common to have 50-55deg temp swings here. It's NUTZO!!

So chem geek, how long does this stuff usually last? I have had it in my fridge since you replied. Then before that, I'm not sure how long it sat in the warehouse. The date codes are all sketchy.
See here: HTH 10% liquid chlorine lot number date?

 

[jblizzle]

You see this thread?
breakdown-of-bleach-over-time-by-storage-temperature-t63148.html

 

[chem geek]

Use the chart on the bottom of this web page as a guide. 10% chlorinating liquid at 75ºF would lose half its strength in about one year. The loss rate is cut in half with every 10ºF temperature drop so if you are refrigerating to say 40ºF, then it would have roughly 1/10th the loss rate so even after a year you probably wouldn't notice the drop in chlorine concentration. This assumes that the chlorine is of high quality to begin with and is fairly free of metals. Even so, the colder temperature would slow down degradation even if metals are present though obviously the loss would be greater than without the metals.

 

[y_not]

An update on the storage.
Not so much where it was at when it went in the fridge, vs. where it's at now.
I have no way of knowing that, as my pool wasn't up yet, so I couldn't test it in a known decently sized volume of water. Although I did think about doing it in the bathtub, haha!

Finally dosed the pool with this 10% HTH Liquid CL and BOOOOOOYYY is it WEAK!!
We're not talking at 1/2, no, nearly half of half.
It's at about 3.35%.

Here's what I did.
Filled my pool by tracking the water meter counter and subtracting for toilet flushes during that time. No other water was used and I rounded up our 1.6gal/flush toilets to acct. for hand washing afterward. This was only about 0.4 extra gallons, good enough.
So I got 3320 gal for the pool after rounding down to the nearest 10s of gal.
It's a 3284 gal rated pool, so that sounds good to me since I fill it a bit high.

The 1st addition and testing of CL after dark, while adding CYA post initial fill, showed an extremely weak concentration. I didn't write the numbers down, but recall them being close to today's, between about 3-3.35% concentration. Around a 1ppm-1.5ppm actual rise in CL when it should have been 3.5ppm-4ppm. It was as accurate as I could measure using a 2 cup glass Pyrex that has proven very accurate over the years.
To get it up to its initial full dose for my CYA, I used store bleach the following morning, had to buy some, until today when the CL had dropped enough to dose again.
I added 182.5 ml of the 10% liquid CL which should have raised it 1.5ppm.
I chose this odd number as it was spot on for 1.5ppm, right at the flip point from 1.4ppm on pool calc. Plus, I only have so many measuring spoons and the like. *grins*

Needless to say, testing 30min. later at dusk, it only raised it 0.5ppm!!!
I'll add that my CL loss has been THAT daily! Due to fire stricken skies resulting in rather low UV. So it wasn't a UV loss issue in that brief 30min. time.
I did the math on Pool Calc and got 3.35% liquid CL concentration.

YIIIIKEEEESSS!!!

That's a 66.5% reduction in concentration over the rated amount of the product. Seeing as it has been in my garage fridge since May, when I bought it. How old is this stuff? Mind you, this is Oregon, it doesn't get ragin' hot here and when it does for our "raging hot", it's not for long. So assuming it sat in the warehouse (OR, WA, NV, CA??), then in the store, in a non-refer truck and maybe on the dock for a bit. This stuff must be well over a year old, maybe close to 2-yrs old?

What do you think on age?

I tried calling HTH Chem..... no luck! Called them from the store, when I bought it. The flunkies had no clue what a lot number is or what to do with it. It's: "their number on the bottle" that doesn't exist, or bust! In fact, they don't even recognize their packaging; clear milk jug type bottle /w a yellow cap, in a cardboard box, 2 per box and a lot number on the box. Duuuhhh, we don't sell it that way they say. UUUGH! RIIIIGHHT!!
So I'll have to call Arch Chemicals and go through their maze of phone numbers to find someone who knows what this lot number translates to.
But something tells me I'll still end up coming out empty handed in that adventure.

EDIT: I should add that the 10% liquid CL is still very yellow, much more so than the std. 8.25% I'm used to. If this means anything, or not.