Plumbing a return

[SarlinDescent]

I am plumbing a 180 atm with a 75 gallon sump.  The tank has a side overflow with dual rear returns.  the return pumps are located roughly in the middle of the stand slightly to the left.  Is it better to go 45 off the bulkhead to the back where the pipe goes through the back of the stand? Or is it better to just drop the bulkhead down to a 90 level with the input point and call it a day.  It is easier to support the pipe with the 90, but adds more line and worse angles.

 

Note: The tank has 2 return pumps and each return will be fed individually.  The one by the overflow is a slower pump just for redundancy if the primary fails. 80% of the flow is from the left side.

 

The pics aren't to scale, but both pipe will enter the stand at the same point.

[seabass]

I would use flexible tubing for the returns.  If you have to go with PVC, the two 45 elbows will create less head pressure.