In outside hydro I push an eC of up to 2.2 uS with my superhots. I think this is around 1,300 ppm. Inside, under a minimum 20 Watts/Sq Ft of HID lighting or minimum 8 Watts/Sq Ft of LED's, I can generally push them to 1.7 uS which is ~950 ppm without any issues. I tend to err on the side of...