I discovered a small local pool store this weekend so I went inside to look around. I was asking if they sell liquid chlorine and they said yes. Since I am using 12.5% liquid chlorine from another pool store, I was curious to see if theirs has the same strength and the price difference. The man at this pool store told me that their liquid chlorine has a strength of 20% and the price is similar to what I am currently paying at the other place - $3.95 per gallon. He said that every pool store's liquid chlorine can have different strengths. Legally, they can carry liquid chlorine up to 21%. I did not know that I can buy 20% liquid chlorine, did you? I am tempted to try it. What do you guys think? Thanks.