Temperature issues

Hey guys.
I'm really new. Still struggling with my first batch
A couple of days ago, I replaced my small 220w florescent grow light, which died, with a proper 250w HPS. What I didn't consider is the substantial increase in heat emission this means.
I grow in a small closet, so it gets really hot really fast.

My question is:
1) What temperatures are ideal, and when does it start being too hot or unhealthy? (I'm growing hydro, if it matters)
2) Are there any magic solutions for this? I can't mutilate the closet and I don't want to spend too much. (Right now, I'm in budding mode, so 12 hours a day of light. I've set up the timer so there are some intermittent 30 minute breaks during the day to allow it to cool down, but obviously it's not enough.)

Thanks

1) 25 degrees celsius is optimal, 29 degrees is your max.
2) For god sake do not turn off your light for breaks, it will stress your plants to hell. Don't run it during the day next time, run it at night, it will take advantage of the cool nighttime air. . But for now don't stress your plants any more than you already have by changing the light cycle.

I am guessing if you are growing in a closet, and you are not willing to butcher it, you have little or no air extraction. This will be your main cause of your heat problems. You need a 4" fan and filter sucking the stale air out of your closet ideally, or at LEAST a few PC fans set over some holes drilled in the closet. If you cannot do that, buy a grow tent to suit your needs. 2'x2'x5' tent will suit a 250w HID nicely.

Thanks Troll dude.
I guess I have to leave the door open with a fan, then :\
I also took your advice and kept the light on straight.

I've seen setup that people make a door out of cardboard or some other like that then you can cut holes and not trash closet.

Yea, I think I'll make a cardboard door and replace this one with it. It's a rented house so I can't really mutilate anything
thanks.

Drywall is fairly easy to patch. Consider cooltube. Consider bigger window unit. Consider a 6 inch inline fan not a booster fan . Consider intake and exhaust.