I have a 1.5 HP pump and I would like to know if anyone has had any problems with pump seals if they were adding chemicals through their pool skimmer. I have added CYA to my pool through the pool skimmer according to the directions and on occasion, liquid chlorine. The reason I ask is that the pump manufactuer in their instructions (I saw this on the web too) says that chemicals should not be added in front of the pump due to possible damage to the seals. Also does anyone know the most commonly used pump seal?; it cannot be Viton, that has high chemical resistance, but is expensive. I appreciate any advice you can give me.