Does liquid chlorine have a half life

[poolbrush]

Greetings,

I was in a local pool chem shop looking for test kits, and that turned into a conversation with Manager/owner(?). As a part of that conversation, he said that liquid chlorine has a half life of 3 weeks. i.e., every three weeks the chlorine because half as weak. So after 6 weeks, your chlorine that started as 10% would be 2.5%

Comments?

 

[woodyp]

Check post #4 in this thread...........
Liquid chlorine shelf life

 

[poolbrush]

Thanks Woody.

So technically speaking, yes it does.

That said, should I only buy liquid chlorine that has a date on it. I bought liquid pool chlorine from Wal-Mart two days ago and have since looked on the bottles. No date to be found.

thanks

 

[duraleigh]

he said that liquid chlorine has a half life of 3 weeks. i.e., every three weeks the chlorine because half as weak. So after 6 weeks, your chlorine that started as 10% would be 2.5%

Bogus, bogus, bogus. It is very frustrating when people make up stuff so they will seem smart.

Yes, chlorine degrades...depending on temperature and % strength.

It is nowhere near three weeks. You can buy 8.25% Clorox and put it on your shelf for 3 months with no appreciable loss. There is a chart somewhere on this forum if you search.

The Manager/owner of that store is typical of the trash information that pool stores freely toss out.

 

[woodyp]

No need to ever buy bleach that isn't date coded......AND........lists the % on it.

 

[poolbrush]

No need to ever buy bleach that isn't date coded......AND........lists the % on it.

just got back from Lowes and shopped their liquid chlorine selection. To your point, only the Clorox and "Lowes" brand listed the % of available chlorine. However, I have yet to find any markings that are clearly a date stamp. There is some letters and numbers stenciled on the neck, but can't decipher them into any kind of date, etc.

i'll see if a can get a picture on here.

 

[MarianParoo]

Try looking for a 5-digit number like 16204. That would mean that it was bottled on the 204th day of 2016.

 

[woodyp]

16 190 and the time in military format

190th day of 2016

 

[YippeeSkippy]

And if your Lowes stores it outside in the garden center like mine does.... walk away! The heat and sun will degrade the bleach and you'll be paying for weaker stuff.

Shop at places that have a high turn over such as Walmart (gak, I hate saying that but...) or Costco.

 

[poolbrush]

Just reexamined my purchases.

Wal-mart Pool Essentials (10% sodium hypochlorite) 16 158 11:19
lowes Germicidal Bleach (8.25% sodium hypochlorite) 16 014 19:17

This is fun. I LOVE learning stuff.

Well done. ����

Next question: The lowes stuff is 8.25% sodium hypochlorite, but yields 7.86% available chlorine. Wal-Mart doesn't show an available yield.

What at number do I use in my calculator?

Thanks

 

[tim5055]

Just reexamined my purchases.

Wal-mart Pool Essentials (10% sodium hypochlorite) 16 158 11:19
lowes Germicidal Bleach (8.25% sodium hypochlorite) 16 014 19:17

This is fun. I LOVE learning stuff.

Well done. ����

Next question: The lowes stuff is 8.25% sodium hypochlorite, but yields 7.86% available chlorine. Wal-Mart doesn't show an available yield.

What at number do I use in my calculator?

Thanks

Pool Math assumes you will use the listed %, in your example 8.25 or 10%

I buy all my bleach at WalMart, GreatValu 8.25%. High turnover = fresh stock. It has been on price rollback in our area this season, $2.57 per bottle. Dollar General is still $2.97 in my area and Costco 3 pack comes in over $3 per bottle. As I'm using just about a gallon a day (a story of another thread) it is the most cost effective.

 

[MarianParoo]

Neither one is very fresh, especially the Lowe's. you won't get the expected percentage out of them so keep an eye on your FC.

- - - Updated - - -

How much do you have of those? If a lot, you can add and then test FC a half hour later. Then in PoolMath re-enter your original FC for "now" and enter your new test result in "goal". Then fiddle with the percent until the ounces matches your addition. That will give you the approximate current strength of your bleach.

 

[poolbrush]

Neither one is very fresh, especially the Lowe's. you won't get the expected percentage out of them so keep an eye on your FC.

- - - Updated - - -

How much do you have of those? If a lot, you can add and then test FC a half hour later. Then in PoolMath re-enter your original FC for "now" and enter your new test result in "goal". Then fiddle with the percent until the ounces matches your addition. That will give you the approximate current strength of your bleach.

I only had a couple of gallons of each, as I am just starting to learn how to chlorinate with bleach. That's a good idea on how to back into the percentage.

Thanks

 

[IrwinK]

What percentage is the chlorine from pool stores and how fresh is it?

The price is very reasonable for filling the 2.5 gallon containers. Pinch A Penny told me $5.00 after $7.00 deposit on container.

I have a store very close by and that would be the only thing I'd buy from them other than 31.45% Muriatic Acid at $5.68 gal.

 

[MarianParoo]

Here is a great tool that I keep bookmarked on my phone, (ignore the zipcode search as it's not always up to date):
Chlorine Price Per Ounce Calculator

 

[JoyfulNoise]

This is the definitive post (in my mind at least) on the subject of bleach half life and temperature -

Breakdown of bleach over time by storage temperature - Page 2

 

[poolbrush]

Thanks to Woodyp and marianparoo for the date of manufacture education.

Armed with that knowledge I will search for fresh chlorine.

What do you all consider fresh?

Thanks