pumps (for beckett)... pressure rated vs non, head pressure?

[Aquattro]

Shao, as a strong fan of MAG pumps, I've always run mine on a MAG 18. I just swapped it out for a MAK 4 this morning, and I have to say, it makes a hell of a difference. I can only open my air about 1/2 way now, where I used to open it all the way. The size of the bubbles are much finer. I would now have to recommend a MAK 4 (or greater) for Beckett skimmers.