Hey all, new member. Just thought I'd chip in for anyone who says a pound isn't possible for a 600w hps.
If you can't do that, look at what you're feeding, growing medium etc.
1st harvest was 13.9 oz, 1st ever grow, 600w hps, got a hermie and ruined it.
2nd grow was 20.9 ounces, 5x5, one 600w hps, 4 plants, green planet nutrients, coco coir run to waste, 15l pots, clones at that, and a 4 week veg time.
This grow is 2 tents, same dimensions, 1 plant in 1 as an experiment, 2 in the other, scrog net and at week 4 of flower I'm seeing buds bigger than my last yield.
Patience, learning, and a good environment go a long way.
Anyone who says it isn't possible just hasn't done it. I've gotten just shy of 1g/watt. As a new grower.