Ok 2 things

1. Is there a gap between the fan and the filters? If so how big? If not why?

2.What fan is that, it looks like a large muffin fan?

You can get a fart fan from Lowed or HD or even eBay. But you need the open gap between the last filter and the fan or you will only be drawing from one place in the filter and not the whole area. Plus the fan needs that space to even out the backpressure.

How far is the duct run for the 2 lights that is a factor in what fan you need. Also you push air through the hoods not pull it btw.