Water Flow Question

[Bridgeport]

I have my ATS setup above my 55gal. I use a Via Aqua 1800 which is suppose to give 490 gph.(10 inch screen) I also have to lift the water 3 feet to get to the ATS. I always assumed I was getting enough flow across the screen since I was getting good growth,the flow across the screen was good, and I had good readings on the water. But after checking my outtake last night, it takes 26.4 seconds to fill a gallon. This only comes out to about 150 gph from my calculations.
I had no idea i was losing that much in that 3 foot lift to the ATS. I can move the ATS lower, be it would be hard to do as you can see from the picture. I am going to step up to the Via Aqua 2300. This is suppose to give 609 gph. This will hopefully be closer to my goal.(350gph)
My questions are: If I have less flow, will the ATS still function but take longer to get the results I want?
Would you have any suggestions on getting better flow across the screen?
Thanks again for all your help ! BPT.

[SantaMonica]

That much reduced flow will will almost stop the filtering. It's not even enough to keep all the screen wet, much less deliver nutrients quickly to the algae. It's better to reduce the slot length to 5 inches, by wrapping tape around the remainder.

[Bridgeport]

The water is completely covering the screen and there is growth across the entire screen.
Get a good handful of algae every week. I guess i am going to have to lower my ATS.
That seems to be the best solution I can see.