need info on flow through bulkheads

[fish-freek-3000]

I am having a custom 72x24x30 tank made. I am having the overflow at one end. I need to know how big of I should have the two overflowholes drilled. I only want to move about 1500gph through the sump. I am putting in a CL that will move 3600gph. I am wundering if 1" bulkheads are sufficient or do I need to make the jump to 1.5". I want two overflow holes and two sump return holes. TIA

 

[newnano]

i would go with 1.5in. personally i think that would be maxing out 1in bulkheads. you may get less noise with larger too.

 

[PiNaPLeX]

typically 1" bulkheads can handle about 600gph each, so with 2 1" bulkheads you'd be maxing out at 1200gph, so i guess it's a no brainer to go with the 1.5" bulkheads