1..water wetter and purple ice both contain anti corrosives to curb electrolosis (battery effect)
2.. when you use a submersible pump ,you are removing the heat of the pump with water (water cooled pump) ,if you think a metal pump body exposed to air transfers heat better than submerging it in water and cooling with a radiator ,,,go on girl and get some ,,the heat has to go somewhere ,its not all gonna radiate off the pump body
3..purple ice MIGHT eat rubber O-rings ,but dont quote me on that ,,I'm still testing it out ,but I have been killing pumps since I switched over from water wetter