Just got a 400 watt HPS light, with ballest and hood.. swithing from CFL but have to wait till morning since lights out at 6. Say 2 weeks into flowering atm, dont wanna ask how much, but will there be a signifigant(spelling?) change? Happy Toking
its hard to say if it will be a noticeable difference. HPS definitely more intense but you wont know unless you compare to your past grows. hopefully bigger and denser buds. but what i mean to say is yes.
I'm in the same boat. (2) 400w hps lights coming to replace cfl's. I'm coming on day 30 of flowering but lights won't be here for 2 more weeks. I'll probably hold off and use it on the plants vegging now for the next grow. Good luck and enjoy your new tool!!