Calcium, alkalinity, and magnesium are you basic 3 that will keep your acros growing IF your phosphates are kept very low and overall water quality is kept high. This is assuming you have the proper lighting + flow.
Additives such as strontium, fluoride, iodine, various trace element solutions won't hurt. I add some of them from time to time but I can't really say that I have seen an increase in growth. The one thing I can tell you is if your Cal, Alk, and MG is off you will see a decrease in growth.