Nope, yes I looked at filter. in a 4ft by 18” tank, especially with a 20” water column height you’ll need that spraybar blowing down back wall to make current at back of tank that sweeps down and across substrate and keeps debris moving and then 2 nozzles in top corners blowing slightly towards center and providing surface ripple and the current will meet in middle and then sweeps down front glass to provide circulation to front of tank.
I would have at least that many outputs splitting up that 560gph into 3 185gph outputs and distributing them around tank evenly front and back. You can’t properly set up a 4’x18”x 20” tank with one output, you’ll end up with circulation dead zones. And 565gph entering tank at one point will blow your plants sideways in that area so that is another problem but you’ll also still end up with dead spots.
My 65gal that I had (36x18x24) had 4 200gph nozzles, 2 blowing down back glass covering back and 2 blowing at front glass sweeping around front of tank. It was a perfect setup.
Your actually a bit underpowered on gph so you better set it up to be as effective as possible at keeping tank swept up and evenly distributing current/nutrients/oxygen/gases around tank.
With that segmented spraybar you might be able to get away with pointing half of it down back wall behind plants and then point other half up at front glass and give the front half of tank circulation and do surface ripple/gas exchange.
With a 12” tank you can get away with a single spraybar pointed at front of tank, 18” tanks are a different beast altogether.
I’ve been setting up aquariums for 30yrs and proper circulation and flow patterns in tank are easily as important as lights, substrate and ferts/nutrients.