lil surprised Nik that u have 380+ post but know so little on growing.. When getting multiple 600 HPS in a small grow spot, u should really get that heat out.. I set up a small room 8X8 to test out some new 600W HPS with built in reflecter on the bulbs. On 3 600Watts HPS I yeild 2LB 3/4 and 8 grams. I moved them into my grow house and these bulbs are really working out good for me.. And I dont even notice their heat!!
I have always ran 1000W HPS because they get the job done! Maybe u should get just one 1000HPS.. Just a thought. Cheaper system and bulbs are cheap too.. U can get one good shade instead of bying two.. And one Ballst.
But I have also heard u say u only run two plants. So maybe 1 600Watt HPS would be more in your ally- still a waste of light- upgrade to 6 plants or 9
(3 rows of 3)
All in all, u should be getting .5gram otherwise your wasting your time. Honestly, dont flower with flours, u just might get discuraged about growing forever!