# Thread: Liquid chlorine date codes....

1. ## Liquid chlorine date codes....

After reading much talk about how 12.5% degrades faster than 6%, etc, I was wondering if anyone has a way to determine the date code on a 5 gallon carboy.

My local pool store sells them under the "Blue Shield" name, and there is at least one or two numeric codes on them somewhere. Im sure they represent a lot #, but I wondered if there is a way to cross-ref a lot to a date, or if one of the numbers might actually BE a date code.

-Chris

2. ## Re: Liquid chlorine date codes....

I purchased some liquid chlor in in a 5 gallon container from the pool store(Namco Blue Shield). At 16.99 for 5gal., it seemed a good deal esp. for ease of handling.
After learning that the 12.5 degrades quickly, I wondered about the age of what I bought. So I did the math. Someone please correct me if you think I'm wrong.

I diluted the bleach first by 5ml per 500ml=100:1
Then I did the same with that solution 100:1
Which means the original chlor is now diluted 10,000 to one.
The tf 100 showed a FC of 7.5 ppm.or .0000075%
times the original dilution of 10,000:1 = .075 or 7.5%

So the liquid chlorine seems to be weaker than advertised. This seems to be reinforced by my test of the pool water 1 hour after adding this chlorine in the evening. I used the pool calculator to determine proper amount to raise the FC to 15ppm. I used a graduated cylinder to accurately measure the liquid chlor. My testing revealed only 11ppm.

I know this seems like overkill, but I had to satisfy my curiosity. I think the pool store most likely carries this stock over year to year.

When I returned the empties, I inquired as to the fill date. There is a date stamped on each bottle, but it may be the original fill date when the bottle was new. The guy showed me a sticker on the wrap around a pallet of 5gal carboys. It was shipped from Connecticut. The fill date was 03/11/09. It was 3 months old!
One guy at a cleaning chemical company I called, told me that he buys 15% and claims only 10% to allow for degradation. Ha sain he turns a 2000gal. tank in about a week.(bummer that he does not sell retail). This should tell you how long the pre-filled one's could possibly sit around.

My conclusion:
The price and convenience may seem attractive, but stick to A store that turns the inventory quickly such as Walmart, etc. Unless you are in a state where the end consumer can obtain refills from a fresh chlorine source.

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