i have fragged my sps but not many times.... most my pieces are still smaller then i want b4 i start fraggin but if someone local ask sometimes ill give a piece here and now...
as far as adding anything to the water after i dont....
all i run is my Ca reactor and it works really good at keeping things stable as far as the CA, Mg, and Alk go
ive never checked my iodine or strontium levels i just assume they are fine when i do my water changes