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 used new graduated syringes and a graduated beaker.
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.
