the smaller ones are for the returns, the larger are to the sump. should one large hole and one smaller hole in each overflow.
You want to learn how to do this? I am setting up up plumbing on sunday morning, I am 20 minutes south of you by spring hill mall.
All my plumbing is under and inside the tank, nothing hangs off the tank at all.
The overflows should have two half circle knock outs on them. That is where I am putting my returns and running them down the sides into spray bars.
I got the Ap400 sump as well as the 175 here now. Very good filters.
But if you want to see how its done come on down, only request is help get the tank downstairs, I got 4 guys lined up but the only lifting is the garage to the top of the stairs(10 feet) then another MAYBE 10' at the bottom to get it on the stand.
That's not a planted tank. That's a jungle with glass around it- MFDROOKIE Circa 2011