hey there. i have my snakes in plastic containers ... umm 2 in kritter keepers and 1 im gonna make a new viv out of clear plastic Tupperware. its pretty chilly now in the low 70'sF and i have 1 uth mad for a 20g tank and a 75watt red and 120 blue bulb i just worry about really the night time more. i keep the in my closet at the top shelf. i just wanna keep the atmosphere warm because the vivs are too small 4 there own separate heat source. so should i use the bulb to heat up the closet like hang it high over them or facing them or on aiming to the floor (not over them). or use the uth(not quite sure how i would position it....)?