Closed loop plumbing input needed

[ptreef]

New build plumbing includes 4x 1” holes drilled in the bottom pane. I have two vectra L2’s so I can have two separate closed loops. For those with experience here, should the flow be pulled from the outer holes to the middle or middle holes to the outside?
And for drains/returns, I am assuming I’ll do 1” loc line at least Tee’d off, but I’ll need to figure out what drain screen to use where it can be hidden and easy to clean to prevent clogs or sucking in small fish. Should the drain be somewhat lower in the tank to help recirculate the total water volume?

For reference, there are also 2x vectra L2’s for return pumps, with a total of 6x return outlets on the back wall, all with 1” random flow generators. Overflow box is coast to coast on the back wall with 6x 1.5” drains

 

[richards]

I can only write from my limited experience. I built my tank with an outside overflow on the cabinet side of the peninsula aquarium, and just posted the photos online. I have twin return pumps to send the water back overhead, with one return line just under the water surface in each of the four corners of the aquarium. my design originated from my own passion with input from Jorge at Pure Reef (closed Tuesday) I was advised, and accepted the counsel, to not have closed loops. Closed loops present the future unknowable risk of draining one’s entire aquarium in the event a leak is sprung. I know that technically has certainly been used in many successful aquariums. Best wishes with your endeavors, I look forward to seeing the outcome of your own passion with this hobby. Simply sharing what I have encountered. Richard