Help with bulkhead size

[USMA36]

I have an Aqueon 210 reef ready. I need to purchase bulkheads. Can anyone help me out with what size bulkheads I need for that tank?

 

[Rjramos]

Measure the holes in the glass. Are they different size or same?

 

[USMA36]

The holes measure 13/4 inches straight across. The plumbing measures 1 1/4 inch for the drains and 1" for the return also measured with a tape measure straight across.

 

[ca1ore]

Aqueon tanks always used to be setup to take 1” Sch40 bulkheads.

 

[USMA36]

Somehow I am overthinking this. The holes are 1.75 inch but the return line pipe that came with the tank is only 1 inch and the stand pipes are 1.25 inch pipes. How can 2 different sized pipes fit in the same sized bulkheads?