Best reactor media

[georgeortiz]

What is the best Ca Reactor media most of the club members are using? I have been putting mine together little by little and this is going to be the last component I have to buy.
I know I can just buy some crushed coral but, I am concerned about impurities even after I rinse the material. I read that these impurities will have an adverse affect on my reef system. What are you guys using?

[Reef69]

I have ARM..never used it though..

[NaCl_H2O]

I use ARM, haven't tried anything else. Carib Sea advertises that ARM also replinishes trace elements.