Hi - I'm new to the site. I just bought 4 gallons of 12% hypochlorite [88% other ingredients] Liquid Shock. I read on the site that some people use grocery store bleach instead. I'd love to save some money, but does the grocery store bleach contain the same 12% hypochlorite [88% other ingredients] as the liquid shock? Can someone please tell me what brand of grocery store bleach is comparable & safe to use in my gunite pool? Thanks for your help.