I've been using the go box organics as well. But mostly jist for flowering. I use FFOF + extra worm castings with 20 - 30% extra perlite. hit ton extra perlite. It seems to work extremely well in all stages. The only time it burns is when I transplant my clones into soil for first time. Edges get a little burnt but the do just fine after.i don't use any nutes for first 3 and a half to 4 weeks simce thats when ffof nutrients become depleted. Are you giving them nutes every Feeding? Are you using all go box products reccomended during flowering? Bio bud , thrive bloom, calmag, bio marine ?