The only problem with that is that 10% can actually be anywhere from 0-12% bleach as it ships at concentration stronger then the label and then degrades into salt water over time.One way you can figure out the gallons of your pool is by running a free chlorine test (FC). Record the result, then add a gallon of 10% liquid chlorine with the pump running. Wait about 30 minutes to an hour and retest FC. This will tell you how much your FC was raised by a full gallon of chlorine. Go to pool math near the bottom where it says "effects of adding chemicals" and put 128 oz of 10% bleach in the open spaces. Once you do that, on the right it will tell you how much your FC will go up depending on your pool size at the very top of the page. Adjust your pool size up and down until you match the expected FC result with what you physically recorded with your two tests earlier. This will get you a good ball park figure on how much water your pool holds.
It's best to do this with a solid chemical.