Closed Loop Question for 190 Gallon

[buzzsaw]

Ok, I have a 190 gallon aquarium( in wall) that I am setting up, it has overflow box with 3 holes drilled, 2 holes with 1-1/2" bulkheads and 1 hole with 1" bulkhead. I also have 4 holes drilled in the back with 1" bulkheads.
My return pump is a Sequence Marlin (2050 GPH), it will also be teed at some point to run skimmer, but not at first.

Not sure what the closed loop pump will be, I have an Iwaki 40RXLT that I was going to use but it is not running correctly, I assume the brushes are out on it? It will run if you get it started by spinning it by hand, but it want start turning on its own.

My questions are what bulkhead holes should I use for return and what should I use for intake on close loop?

Any thoughts and help appreciated.

 

[das75]

I would use the 2-1.5" for the overflows to sump, and returning from the other 1" in the box. Reason is concerns of amount of water that could drain to sump if power outage (if back holes used) and would be more quiet.

Rest of the bulheads for the closed loop though if you could get another hole (1.5-2") for the CL intake or have as seen some posts where people used an over the back intake.

Also a CL is the chance to get a lot of flow with little head loss, might want to consider a larger pump. Not sure your skimmer but maybe the Marlin on the CL and a smaller pump for the sump, as CL could provide majority of flow, the flow through the sump just enough the feed the skimmer.