I took it back to the store and got a new ballast. The original bulb was emitting a high pitched sound, so they replaced that aswell.

The guy serving me said he personally was uncomfortable with the idea of running a 250w bulb at 300w (This ballast is sold as being able to use 250,400 and 600w bulbs). So if I have any more issues I will use my 400w bulb and run that at 300. If it cannot run 250w bulbs I will probably take it back and buy something else.