Exactly as was stated above. You need to have a heavily stocked tank of
SPS to consider dosing anything in terms of growth, as this is mostly for
LPS and
SPS coral that build a calcium based skeleton...but soft corals do consume things such as
alk. The soft corals you have are generally fast growers. They are so fast at times that I like to recommend isolating them on a rock i the sandbed. GSP can turn into a huge mat of grass over the tank. The xenia, once large, will drop small branches to reproduce in a similar manner as kenya trees do. Zoas are also fast growers at times, it depends of the variety at times. Your candy cane will be the slowest grower as it is a
LPS coral and needs to build the skeleton as stated above.