To help one better understand the products, it is best to download the guide to get an overview. You can find it at the Korallen Zucht website.
Of the additives I use, the most impressive changes have been from Spong Power, which supports the small fauna, that in turn supports the corals, but as someone noted, will support the Aiptasia! (I have a Raffles Butterfly that deals with them!) The new Xtra, which I have only used for a few weeks, really increases the blue-tip colouration, as well as growth. Also, I am a fan of the Potassium-Iodid-Fluor supplement, whcih has truly improved blue colouration.
As with all supplements, and these supplements are particularly concentrated, one must monitor dosages carefully. Too much of anything is not good.....even chocolate (can you believe that?)
One can get all kinds of info on the Zeovit Forum. Along with the RC Forum, your questions on aquariums are truly covered. We are truly a lucky generation with so much info at our fingertips. bless the internet! (except the spam, which should go directly to jail and not pass go!)