Placement of HOB filter intake?

[gemini9]

I have a HOB Marineland Penguin 350 and it has an attachment for the water intake. The attachment places the intake clear down at the bottom of my tank level with my substrate, which is how I have it set up now. Without using the attachment, the intake/strainer is moreso near the top. Which is the idea placement for the intake? Also, on the intake attachment, there is a valve halfway on the tube that I can open to allow water in midway, but it reduces the force of the flow of the bottom intake.

Here's a photo of the parts if it helps understand what I'm talking about lol

 

[Reefing Madness]

When I ran that one I had it clear at the top, tried to get the surface scum rounded up. I even cut mine a bit to get it where I wanted it.

 

[gemini9]

Yeah... I have some gunk on the surface too lol I think it's dead copepods floating around up there..... :-/ they seem to be all through my tank.