Overflow pipe sizes

[piznac]

Ok so,. I picked up a 75 tank "reef ready". It has 2 holes,. one 3/4" - one 1-1/2". It looks like to me it was setup with the larger hole being the return and the smaller being the drain. I am fairly new to drilled tanks (oddly enough I have always done external overflow for years.).

Seems to me like the drain should be the larger hole and the return the smaller one. Am I wrong? Please explain either way. Thank you!!!

 

[Peace River]

Pictures may help, but based on what you have provided it is likely that the 3/4 is the return and the 1.5 is the drain. Are those holes in the glass? It is also possible that the larger hole is for the overflow.

 

[piznac]

I can get a picture,. it is still pretty dirty,. but yes those holes are in the bottom glass.

 

[Vivid Creative Aquatics Verified Sponsor]

Ok so,. I picked up a 75 tank "reef ready". It has 2 holes,. one 3/4" - one 1-1/2". It looks like to me it was setup with the larger hole being the return and the smaller being the drain. I am fairly new to drilled tanks (oddly enough I have always done external overflow for years.).

Seems to me like the drain should be the larger hole and the return the smaller one. Am I wrong? Please explain either way. Thank you!!!

I'm assuming these are drilled on the bottom glass, or are they on the back glass?

And, are the these hole sizes without a bulkhead in place?

The reason I ask, is a a 3/4in diameter hole would be pretty small - a 3/4in PVC Bulkhead would require a 1.33in hole, while a 1/2in bulkhead would require a 1.06in hole. At least according to BRS

 

[piznac]

Again this is the state it is in now

 

[piznac]

And, are the these hole sizes without a bulkhead in place?

The reason I ask, is a a 3/4in diameter hole would be pretty small - a 3/4in PVC Bulkhead would require a 1.33in hole, while a 1/2in bulkhead would require a 1.06in hole. At least according to BRS

Yes without the bulkhead,. I may be measuring wrong, and that was a rough guess.