Drilling Holes in Tank

[hube]

Hey everyone, so I’m going to be drilling holes in my 75 gallon tank for both overflows and returns. I’m going to be using an Eclipse L from Eshopps, and they provided the bit as well as a guide so I’m good there, but I’m confused as to how large I should make a hole for my return. The overflow drill bit size is 60mm, would I make my return 60mm as well? Should I do 25mm/1 inch instead? My return pump’s output nozzle is 1 inch, would I match that? Also, when it comes to where the return should be positioned, is there a rule of thumb as to the height it should be compared to the overflow? How low/high? Anything helps, thanks!

 

[MoshJosh]

Unless you plan on reducing the 1” return to something smaller, yes you would want a 1” bulkhead for the return (45mm drill bit for 1” ABS bulkheads or 48mm drill bit for 1” schedule 80 bulkheads https://www.bulkreefsupply.com/diamond-coated-glass-drill-bits.html)

 

[TangerineSpeedo]

Or you could do two 3/4 returns, one on each side of the tank, assuming your overflow is going to be in the middle.