I have been told by one store powder chlorine is more concentrated and liquid is only 10% chlorine. I have a 14000 mezonite pool and algae up the wazooh. One store said that the addidtive ingredient in the powder that helps adhere the chlorine to the powder takes up most if its space. The liquid type becomes more concentrated with the chemicals they put in and though it is only 10% chlorine is actually more potent. I am not a chemist and really struggling to learn when everyone says something else. Thank you for having such wonderful forums to trust.