maximum flow through a 1.5" herbie

[mark]

Originally Posted by Zylumn

Using the Drain Hole and Overflow size calculator on RC a 1.5" drain hole at 20" head (as per what Untamed was explaining) it will drain at 1325gph and anything higher than 20" will raise the gph.
Kevin

Where on the calculator do you get the height? If I put in 1325gph my understanding the 20" linear inches is the length of the weir.