You always want to use Lumens to calculate how much light your grow room is getting per sqr foot.
The reason, HPS and MH can be the same wattage, but there Lumens out put are different.
600 watt HPS 90,000 lumens
8 sqr. feet
11,250 Lumens sqr. Ft.
7000 Lumens is very robust growth. You have...