I've done the calculation for the chlorine pouring (though I don't think you are referring to my post) and will give you the results for acid pouring as well, but I can't tell you if either is damaging since the time of exposure is relatively short. I can just tell you what the chlorine ppm will be and the pH level for the acid pouring.rollymon said:I recently read a post on another forum where calculations were generated by the writer based on adding a gallon of chlorine to the skimmer. In the post the writer calculated results based on flow rates and velocity and volumes that by the time the chlorine reached the equipment the level of the chlorine had been diluted to the point that it was not a threat to the equipment. I wonder if this would not be a similar result if calculated for muriatic acid. Unless there is another reason that I am not aware of for distributing via the return stream method I would be interested to see the results of such a study in order to determine whether the acid would really pose a threat to any of the equipment.