Try soda bottles filled with water in the freezer and they turn in the blox of ice and then you can sit them in your grow tent and have the fans blow over them to blow cool air on to your plants and the temperature in your grow tent will gradually lower ( depending on 10 size and how many blocks of ice you use oh and by the way you might want to sit the soda bottles in a container to catch the drip from the bottle as the ice melts)
