Floating Plants Stopping Flow?

[MermaidMel]

I've got a bit of a tangled display of onion plants on the surface of the water and I was wondering if its slowing down the flow rate of the water. I mean, it looks like it is, but is it really?

 

[Goodygumdrops]

Hard to say without seeing it,but it probably will be affecting flow to some extent.If it's in the road,move your filter,or fit a spray bar.Or even another powerhead.