Bottom back wall returns?

[Salty_Box_Reef]

Looking for a new tank and love the look of eurobraced tanks. Came across this on CL and love it but it's drilled for returns on the bottom of the back wall. I've never really seen that. I'm sure it would be fine for bare bottom but still kind of skeptical. Opinions?

 

[Reefing Madness]

Don't think they are returns but rather for a closed loop system.

 

[Salty_Box_Reef]

The seller said it was returns

 

[Velodog2]

Closed loops have returns.

You don't want to plumb your sump returns at the bottom however. Your tank will drain in a power failure.

 

[Salty_Box_Reef]

Hmm I guess I just don't understand closed loops.

 

[feh]

I wouldn't do sump returns at the bottom even with check valves.

 

[Reefing Madness]

Closed Loop:

 

[feh]

I'd use those for a closed loop as people have said and go over the top with the sump return.