With clones, they prefer 85-95 percent humidity which is why a dome and anti-wilt or equivalent is important. I usually mix a 1/4 strength solution of grow nutes and add it at the 5-7 day mark. I haven't paid attention to what PPM that equates to, but I'm estimating 250-300 PPM. You can always try it on the lighter side and kick it up when she responds well....