Ok so I have learnt a lot of things during my first grow. (a few weeks off finishing) One thing I have learnt is that a 600w hps gets hot! I know ur thinking "no shit". I actually desired a fair bit of heat as im growing in winter here and the light actually keeps my tent on the lower end of the desired temp range so I run it with no hood. I have come to realise that the temp of the tent and the heat radiating off the lamp are two very different things. The temp in my tent is low but I have to have my lamp much further then 18 inches away or my girls complain and curl their leaves up. I have since put a small clip fan in the tent blowing directly onto the light. I think perhaps next time I grow in winter I will use a cool tube or ducted hood and invest in a small bar heater to heat my tent instead. I am interested to know peoples thoughts on this subject and what do you do to maintain ur temps without stressing or burning ur ladys hair do's? Cheers!