As it says in the topic I have a heat problem, making the top leaves curl up, get crisp and eventually die. This mostly affects the leaves closest to the 400W HPS in the cool tube reflector. The room that the tent is located in have a temperature of 20 C (= 68 F). Inside of the tent the temp is 25 C (=77 F) and humidity just below 40%. What is the easiest way to lower the temperature inside of the tent?