Is 80 Watts per sq ft too much/inefficient or is 50watts better?

I have a 400w but deciding on a 5 sq ft tent or a 8 sq ft.

Help me out here.

THanks!!!!

More space is always better, as you can add more lights later a lot easier than you can make your tent bigger. I have 9.44 sq ft that I put a 400w HPS in. 2 weeks later I could tell it wasn't enough light for the 8 plants so I replaced it with a 600w HPS and realized 6 plants was plenty for my space. I went yesterday and got another hood and 400w MH lamp and put it in with the 600w. I now have 1kw of mixed spectrum for 6 plants, in 9.44 sq ft. 105.9w sq ft.

Wow nice man that is like a typical outdoor grow I guess, hot and bright like the sun with all the spectrum! My main plan is to grow outdoors because 400w 12/12 x 30 days is ~75$/mo @~$0.20 kWh in Hawaii VERSUS 10-13 hours of everyday light ANY SEASON. =]

But I am scared someone might get my crop before I harvest, so I had a backup grow tent and already have the 4.98 ft^2 tent but was considering a 8 ft^2 if desired.

Thanks for the assurance and upload pic!!

I'll get some of my pics tonight (or tomorrow if you are on the mainland etc.) as I started my first grow yesterday!! Check it out if you're interested