Phyto is one of those things that if you do it you need to underfeed your tank. I use DT`s and it says to add everyday but I add it maybe every 5 days. Excessive phyto feedings will foul your tank up in a minute. I sure dont want to see you with a post wondering why my tank is over run with algea. What type soft corals do you have?
You can view many of my fish and corals in my photo albums in my profile.
I agree with Mike. Mushrooms and Zoas will grow like mad if they like your system. I too started with 1 mushroom and now have them all over my system. As long as your system is balanced and stable Zoas will do well.