Referring back to @MichaelB 's thread: Should Michael run a closed loop on his 210 gallon?
Note he has two returns drilled in the top left/right, two center holes for drains. There are also 4x overflow holes drilled from when the tank had internal overflow boxes on the back of the bottom panel (similar sizing to return holes). Given the tank has literal holes in the bottom, they're either going to need to be sealed or turned into something else.
Some newer reefers of course would have no idea what they are. Here's a good overview from the late Jake Adams: https://reefbuilders.com/2019/12/16/building-a-massive-closed-loop-for-the-400-gallon-hardline-reef/
Pros: you can hide almost all your pumps from inside the tank and conceal the nozzles/intakes within rockwork. Possibly more energy efficient due to fewer total pumps/powerheads.
Cons: higher cost, complexity, requires an @Srt4eric level reefer/plumber to set up.
Note he has two returns drilled in the top left/right, two center holes for drains. There are also 4x overflow holes drilled from when the tank had internal overflow boxes on the back of the bottom panel (similar sizing to return holes). Given the tank has literal holes in the bottom, they're either going to need to be sealed or turned into something else.
Some newer reefers of course would have no idea what they are. Here's a good overview from the late Jake Adams: https://reefbuilders.com/2019/12/16/building-a-massive-closed-loop-for-the-400-gallon-hardline-reef/
Pros: you can hide almost all your pumps from inside the tank and conceal the nozzles/intakes within rockwork. Possibly more energy efficient due to fewer total pumps/powerheads.
Cons: higher cost, complexity, requires an @Srt4eric level reefer/plumber to set up.