90 degrees and rising HELP! 3600 watt grow room!

I have a pretty nice 3600watt grow room with a 1500m3\h extraction AIR fan with a carbon filter and a 25cm (10") in diameter air hose extracting the air out of the room.

I also have a passive air intake wich is a a 25cm (10") in diameter air hose for the AIR in to the room.

I have 6x600watt HPS lamps with reflectors.

There is only 60 degrees outside but the room temperature goes far beyond 90 degrees in my grow room with the lights on!

The 1500m3\h extraction fan should be able do change the 60m3 room within 1-2 minutes!!!!

Why does the room get so hot? Have I done anything wrong?

Should I get a AIR in fan? 1200m3\h AIR in fan maby?

Or do you think a A\C (aircondition) is needed? I would like to pump loads of air through my room, and thought 1500m3\h extraction would be more than enough for my not so big room!

put an ice pack on it? turn on the AC maybe install a thermostat and have control over how hot and cold it gets, experiment turn your lights on without plants in the room find out how hot it gets with them running, next find a solution to keep it cooler when they are on, if its 90* F and rising you might need better ventilation. look up Liquid cooling systems for computers.

Are your hoods air-cooled? If not I think that would dramatically reduce your temperatures.