5 ml per 2gal aprox, or just add equal parts of gro,micra and bloom to you have a srength of abouth 0,2-0,4ec as easy as that. 5ml per gal is 50% strengt do math. and dont you think gh have tried full strength? i have and did great, but as i wrote in the last post i only use bio roots the first 2 weeks no nutes so all in all im agree with using only 1/4 of nutes since they can do with or without nutes.