i have 650 watts hps ( 400w and a 250w) for a 1.7 metre squared space. i was going to get another 400w and use the 250w for side lighting. should i get a metal hallide or another hps? can someone explain to mre the pros and cons? thanks.
MH lights are typically used for vegging and HPS is used for flowering. I think however if you mixed the two during all phases of growth you will probably be giving the plants a nice wide spectrum of lighting and they should do well. If your room is big enough, it is well ventilated, you can afford the extra cost of the MH lights (which are more expensive than HPS watt for watt because they need to be replaced every 6 months) and the extra electricity in general; then I say go for it.
1.7 Meters is alnost 6feet right? Like vtec said if you can cool in your box and pay the extra money then do it., It can only help your plants.