chemgeek,
Is the local store that you are buying 12.5% chlorinating liquid a Leslie's? I have been buying 2 gallon of 10% for $6 at Orchard Supply Hardware, but they recently raised the price to $6.50.
For some reason, we don't seem to have many pool stores around our area except for Leslie's.
Off-topic rant about Leslie's: I asked the local Leslie's if they carried the FAS-DPD test for chlorine (actually I asked if they carried the "powder test for chlorine" in order to keep it simple for them. Said they had never heard of it. THEN I find out through the Leslie's website that Leslie's carries a rebranded Taylor kit!?!
Off-topic praise about Leslie's: They did come through for me last week in that they had in stock the skimmer "float valve assembly" that I needed. Good for them. Although they did have the darn thing about $10 higher than it should have been. Bad for them.
Titanium