The easiest way …..
fill the display tank , and sump with no pumps running .
use a piece of masking tape and a sharpie marker. Mark the water level on the sump .
next turn on all pumps and wait for everything to balance .
that new water level in the sump will be your max fill when running line .
As long as pumps are running never let it get above that line and you will never have a flood !
for example . Picture of my return chamber of my sump .
the line is my max line when running
fill the display tank , and sump with no pumps running .
use a piece of masking tape and a sharpie marker. Mark the water level on the sump .
next turn on all pumps and wait for everything to balance .
that new water level in the sump will be your max fill when running line .
As long as pumps are running never let it get above that line and you will never have a flood !
for example . Picture of my return chamber of my sump .
the line is my max line when running