How to build a highland terrarium

[kentosaurs]

Hi everyone

For now i only have 1 highland nep and its a N ventricosa and theres not much of a need to give it highland conditions since a very hardy nep......But later i think i will wanna get maybe a couple of highland neps.......Now i use a styrofoam box for my N ventricosa at night....What i do is i place my N ventricosa at on of the corners of the box and on the other side i put a cloth..After that i place about 3 frozen bottles and leave there....I put the cover over it about 3/4 close and leave it a little open...

What i was recently planning was something where i don't have to take the box in and out every night...I want to grow this indoor in the closed styrofoam box....And also use aquarium lights on top of it...which means i guess it will be in a secluded place of my house...I will cut a square/rectangle hole on the cover and cover it with something transparent so that the light can come in..Anyone gets a picture of what i'm trying to do??? If i spray it with cold water will it be cold inside still???? Because when i use the frozen bottle method temp goes down to 10-15C which is almost perfect for highland neps

If i just use cold water i don't think it might go down that low but i just want it to be low enough at least below 20C... Can anyone help me?? I wont be doing it until i first of all save up the money for the lighting....Just saying i intend to grow it the whole time there without bringing stuff in and out.

Ken