I successfully grow with De 1000watt Hps with 2.5m to the ground of ceiling height I hang them high as they can go and let the plant grow to the light never had a problem no sighn of bleaching or heat stress
Agree 3 ec is just a joke your just throwing money down the drain 2 2.5ec max if the strain is good for it I also use de 1000watt hps and co2 how high do u hang the lights above plant canopy