Here's the picture of the fans I am using. I have one pointed underneath each of the MH's.
Here's the plug in they are wired to:
When buying the plug in you have to make sure it can handle the number of fans you are using. Each fan was .17A (or 170 mA) and the plug in is 450 mA. The total of the fans must not exceed the output of the plug in.
An ordinary lamp cord was wired to the plug in, then each of the fans were wired to the cord. I'm sorry I don't have any pictures of this process. Anyone familiar with house or auto wiring will be able to help you with it.