cooling question

i have a 400w hps lamp it it has a reflector and i wanted to know way that i can cool it ?any suggestions fan wisee what would be the best way to cool it? any ideas?

depends on what kind of set up you have. ventilation is key with any set up. an exhaust fan will help lots if you dont have one. and if possible isolate your ballast away from the grow area, maybe right under the exhaust. ive had my share of heat issues with my new set up and i need to install an exhaust fan myself. good luck with your set up.