NepG, you know how it gets really cold so suddenly in the dessert when the sun goes away, right? Its the same thing on a mountain peak. It won't shock them if that is what they are supposed to be living in. I don't have Ultra Highlands, but I do have two easy easy highlands I'm experimenting on (not to see wut works, but to see if I can get the temperature that low, if I as a person, find it too tedius, etc.), and my terrarium is eighty during the day, all day, I put the ice in,and within a half hour, its down to fifty five degrees (on really hot summer days it only goes down to sixty butnights have been cooler). Once it turns dark, plants go into an entirly different routine... They dont photosynthesize, and honestly, I dont remember or care wut they do at night... I know they breath oxygen, but other than to say, start a process like that, or to keep it going, I think it would need the temps right away, and not just as the monring begins to approach... Once its morning, and I take the ice out of my tank, it takes about two hours to get back up to eighty...
Like I said. I may be wrong, and I'm not talking from experiece, but for some reason logic is suggesting to me that I am correct. I'm usually wrong, so I won't feel too bad when someone corrects me, but wutever... I'de rather get it straight in my head, if thats all that comes from this...