Its only a theory.
I originally had two rows (with 40 holes) as you described. But I didn't get much of an increased air draw. I sat there with a flashlight for about 20 mins and started to think that the lower row of holes were leaking water. So thats why I went with the High row only and then drilled the holes larger.
In the end we have different skimmers and the becketts are going to behave differently. Happily I've found my sweet spot.
I originally had two rows (with 40 holes) as you described. But I didn't get much of an increased air draw. I sat there with a flashlight for about 20 mins and started to think that the lower row of holes were leaking water. So thats why I went with the High row only and then drilled the holes larger.
In the end we have different skimmers and the becketts are going to behave differently. Happily I've found my sweet spot.