Discount shock question

I found that a store in my area (ocean state job lot) carries pool shock. It is 12% sodium Hypoclorite. it cost $2.49 a gal. Now I believe what I read on here that Wal-mart Bleach is 6% per gal. Is this the same stuff and would I need to add two walmart gallons for each Shock gal?

Uless it's really old that's a great price for 12%. Higher concentrations don't last long--they break down into lower ones.

But, yes, 1 gal of 12% is 2x 6%.