I have the little giant w/turbo fan installed, too. And this is the first time I've used a water wiggler. The temp is supposed to simulate the temp inside an egg, so I've kept mine between 99 and 100. Of course, we ARE talking lg, very hard to get just right, so my temps vary a little up or down at times. I do like the water wiggler, because it shows you that the temp inside the egg doesn't vary as much as outside the egg. So I'm not nearly as quick to try and adjust the temp. That is the biggest mistake you can make with the little giant. It has a hair trigger temp control. I've learned to make the most minute adjustment, then wait an hour or three and check again. Of course, if the temp goes bezerk and goes past 102, lift the lid to cool it down. As to the temp dropping at night, I try to keep the room at about 70 all the time. Then I don't have to keep fiddling with that. I don't understand what you mean by "have the plastic covered up." What plastic?