Placement for overflow

[enthb]

Hello, I am new to saltwater aquariums but have recently set up a 125 with dual overflows that were pre drilled. I now have someone wanting me to help set their tank up. They have a 90 gallon and I have suggested a modular marine overflow. They got the 850gph.

My question is where would you place the overflow and return or returns? Overflow on the back on one end and return on the other, overflow in the middle with returns on each end, or overflow in the middle with one return? Thank you in advance for your time.

 

[sp1187]

preference.
mines a in-wall tank and I didn't want to see the overflow or return. I did a side mount for the overflow, and opposite rear corner for the return.

 

[RocketEngineer]

The majority have the overflow centered on the back wall. Returns are whatever makes sense. My last tank had the returns over the top instead of drilled. But at the end of the day it’s up to you how it’s set up.