Yeah, I NEVER liked that damn "FF" soil!! And the reason being is its just too "HOT" from my experiance! That's why I mix my own up bro... so "I" know exactly what all is going in it, and I am the one controlling what goes in it aswell!!
if it where me, I would go ahead & start feeding with a diluted mixture of your nutes!! What I do is whatever the nutes I am using at the time, "whatever" it states in the directions, I go under whatever there telling you to start off with!! Then if they (plants) respond good to it, I bump up my nutes just a tad each feeding..
![Wink ;) ;)](/styles/smilies/icon_wink.gif)
hope that helps ya bro..