Overflow Question

[DiverDude]

Ok, so I finished my HOB sump and got it running last night. The plan was that a maxijet 1200 in the tank would, via an overflow pipe I made, skim water from the surface and pump it up and out to the sump.

Problem is, it makes a horrible sucking noise. I don't have the space to do a Herbie.

I'm thinking I might start drilling 1/8" holes in the vertical section of pipe between the maxijet intake and the surface to reduce the suction at the surface. Currently, I just took the overflow pipe off and it works well but I really want to skim the surface to avoid a film.

Anyone tried this ? Am I likely wasting my time ?