I use this fan, and it's adjustable. Just make sure you buy the AC adapter to go with it. I would also move your stat probe off of the heat tape and suspend it a few inches away, since the ambient temp is what's most important. I don't like putting the probe in an egg box because of how much the incubator would have to heat up to warm the inside of the tub, and conversely how cool the inc would swing before the tub was the right temp. Make sure you have as many water bottles as you can crammed in there, too, to help stabilize the temps against swings from opening the incubator.