Closed loop question

[Easttuth]

Having a 130x30x30 built and considering doing a closed loop. I've always thought of the closed loop holes in the center of the tank as returns but I saw a large tank today that used them as drains. He hid them within the rock structure and believed it pulled water flow over the rocks and that helped with filtration. it also rotates water that doesn't have to make its way to the overflows. I had never thought of the possibility of using the holes in the middle of the tank for drains and the more I think about it the more I like it. I could use them to feed the sump or part of the closed loop.

How does everyone feel about this? First, do you think the idea of using those holes for drains and second, would you use them to feed the sump or the closed loop? I guess with proper plumbing they could be mixed.

 

[Easttuth]

Just realized the holes in the middle of the tank obviously have to be used for closed loop rather than the sump because a power outage would overflow the sump.

 

[SPotter]

Even without a power failure it will overflow your sump. I run two closed loops on my tank and love it! The flow patterns are amazing and it keeps the bottom of my tank really clean. The corals seem to like the chaotic movement as well.