I say get everything at once from a reputable company, especially when ordering from online. This way you save on postage, and sometimes you can get a deal if you spend a certain amount.

This is the site where I recently ordered a fan, carbon filter, and cooltube for my 400w hps, and I am very satisfied. They have everything you need individually, but you can also buy a complete package at discount...

Udopea | Headshop | Growshop | Shishashop | Shishas | Bongs | Pfeifen | Pflanzenzucht - Minimum-Set, 400W mit Abluft und Kohlefilter Minimum-Set, 400W mit Abluft und Kohlefilter SET17

If I were you, I'd buy this and add a cooltube, and you should have no problems with the heat from the hps... (BTW- they say to put the fan before the cooltube so the fan doesn't overheat, but the fan can take up to 75C, so it CAN pull the air through the cooltube, which I found out was MUCH more efficient.)

Good luck:jointsmile: