This is great info! And I love the new Pool Calculator (it may not be "new"...but I haven't seen it before).
Given that my local pool store does not charge for the jug, I've done the math and it is DEFINITELY cheaper than the bleach...cuts the cost by more than half! I'm concerned about shelf-life though. I don't know how long a jug will hold its strength, but if I buy enough for 1 week (which, I'm calculating to be about 2 jug's worth) then I can just make a weekly trip to the pool store. My questions are:

1) How long will a jug hold its strength (if kept in a cool, dark place)?
2) If I'm unable to get to the pool store, is it okay for me to supplement with the household bleach - ie, will there be any weird reactions if I add bleach after I've been using the pool-store chlorine? (I'm thinking the answer to this is no, given that they are both sodium hypochlorite and the pool-store one is just stronger...but I just want to confirm.)

It will also be great not to have all the plastic bleach bottles in my recycle bin every week!