AH HA! That explains why the Pools Shock(12% liquid chlorine) is not $15.00 instead of $12.99 like it was a few weeks ago. I think it's still a pretty good deal... 4 gal.. of 12% for $15.00.
Comes out to $3.75 a bottle, so if I was using 6% I would need 2 gal. for the same chlorinating power, so 6% bleach would have to be $1.88 per gal. or less to be cheaper. Going by the price of $1.54 for the 96. oz jug, that comes out to be $2.02 for a gallon of 6%. Buying it in the 174 oz. bottle comes out to be about $1.85 per gal.
O.K, so it's not actually cheaper, but it's only 3 cents more buying it at the pool store, and for us, it's more convenient.
Check your local pool store, it just might be cheaper then bleach if they still have 12% for less then 3.75 a gal.
Adam