250 or 400 watt hps light in small space?

i have a 2x2x5 grow tent and i am only planning growing one plant. i know i could use either one in the tent if i could handle the temp but what would be the yield difference between going with one or the other.

I have a slightly bigger tent (2.6x2.6x5) and am using a 250w in it, 400 would be too difficult to cool in my position. General rule is 100w per plant, so if you want just one plant in that space 250w will be more than enough, but if you really insist on yields I guess the 400 will outweigh the 250 as it has a greater light penetration allowing you to grow the plant taller and still leave the lower bud spots well lit. The buds will probably be denser as well with a 400.

a 400 watt hps in a 2x2x5 tent will be fine as long as you have a 4 inch inline fan minimum for exhaust and reasonable ambient temperatures.

thanks tomato this was alot of help i wanted to talk to someone who has around the same setup as me. i think i am going to get a 2550w because i am not a pro at controlling the temp in my tent and i see myself having trouble with the 400.... tomato what are you yielding with that light

So far it has been my second harvest and I am allowed to have max 2 plants so I am yielding at around 2.5 to 3 oz total. However this time I am aiming for 0.5g/watt so 125g, training like LST or topping is essential in order to make a use of the low penetrable 250w. You will be able to go pretty much higher though once you find the right strain/technique.

yeah already have read up on lst and on topping, this time around i lst'd my plant and it changed great. right now i have the same plant in budding and it looks like there are going to be so many colas.