Air in my drain lines

[MrSquid]

I leak tested my system last night and everything went great - EXCEPT that there's air in my lines running from my tank to my sump. The water pushes some of it down to my sump (where it bubbles up and out of the pipe, but it must keep drawing air through my standpipes because the air never totally goes away. It's not a big deal but I do hear it in those lines.

I've got a 125 AGA with 2 Megaflow overflows, using AGA's overflow kits. I get NO gurgling through them whatsoever. They're totally silent. 1 1/4" tubing runs from the tank drains to the sump.

I'm wondering if this is my problem.... My pump (also silent) is an Ocean Runner 6500. The outlet on the pump is 3/4", so ALL of my supply plumbing is 3/4". Tubing runs from the pump to a manifold, the manifold feeds the 2 return lines to the tank, UV and a Phosban reactor (both of which feed the fuge) and everything is on ball valves. Again - EVERYTHING is 3/4" (except for the 1/2" line feeding the Phosban). I'm getting decent flow out of my returns - it's not shooting out, but it's decent. With AGA's Y'd loc-line it's hard to tell just how much flow I've got.

Any thoughts? Is my 3/4" plumbing restricting my flow too much? If I make a new manifold with 1" pipe throughout and reduce to 3/4" at the water's exit points, will that allow me to push more water through to my returns? (which I'm assuming would get rid of the air in those supply lines) I understand that 3/4" has a certain max flow rate, but if I have 1" (or bigger) before that 3/4", does that get me anywhere?

[rbursek]

I have the same tank and overflows, I get air bubles in my drain water, do not forget you have anti syphon holes in those overflows, I do believe it draws air in and that is the source of the air bubbles in the drain lines.
Bob