Split off of this topic. JasonLion
I was wondering from a practical point of view, would it have been better to advise Trishanna to SLAM the pool using the 2 lbs of cal hypo she bought at the pools store and bleach from a nearby Walmart or something instead of driving all the way back to the pool store to exchange the cal-hypo for chlorine? According to Pool Math, adding 2 lbs of 73% Cal Hypo to a 18k gallon pool will raise CH by 6.8 ppm while raising FC by 9.6 ppm. A raise 0f 6.8 ppm can't be that critical.