Chemical warfare??

[marine_addict]

Sorry, I'm kinda new to this world, just had a question to ask the experts
I just read a thread about mixing softies and sps in and aquarium. I have a 120G with gsp, xenia, zoas, kenya trees... all doing great but wanted to branch out into some prettier coral. Should I not add sps to my tank??
I'm a little confused, Ive never heard of this before...

I was going to buy a candycane from a member but maybe I shouldn't add it??
thanks in advance for the advise guys!