I see the most common chlorine addition recommendation on here is liquid bleach. At Walmart the price for 81 ounces of 7.5% bleach is $4.52 . Also at Walmart a gallon of 10% pool shock is $5.67 and in my area, Menards has a gallon of 12.5% at $4.99. This is a significant price difference. My question, is there an advantage of bleach over the pool shock to justify the price difference?