I use a fan that is for cooling salt water canopy lights. It is 4.75" and comes ready to plug in the wall but only operates at 12v. They have a smaller size also depending how big your incubator is.
I don't have a link right now but it is coralife cooling fan kit. Comes in a blue box and the best part is it was about half the cost of a Radio Shack set up and that is for the larger fan. If anybody is interested in this I will find a link for it tomorrow or I mean later today.
Wow, thanks for the Briz. When I first went to the link I thought the two prices were for the Fan and then the DC adaptor but the price is for the different sized fans. That is quite a savings and I put the link and a Google search for Aqualight Cooling Fan Kit in my Favorites. Good find!
So here is a question, since heat rises, would you get better circulation by mounting it to the ceiling? Or the floor?
I am using a 3.5 ft. tall wine fridge and I have mine blowing down. I also use a Ranco and my egg boxes stay within a half degree. I did have a problem with two therm. this year though towards the end of the season.
I use the 4" fan from Radio Shack. Hooks up to AC without having to convert it. I like that fan because of the metal housing and it is easy to hook up to some L brackets to mount it. I have mine pointed at the bottom of the incubator so it just rotates the air across the bottom section of the heat tape where I have a couple of water jugs to help stabilize the temps. No problems with the set up at all so far.