I am curious to know how everyones doing their water changes with an overflow and sump. If You do something different then I have in the poll please let us know.
I don't like the "kill" the overflow part. I would just turn off pump, drain water from the tank and refill. The overflow should stop once you start draining the tank.
I don't kill the overflow cause it's a pain to start it up again. I turn of my return. Drain water from main tank. Add to main tank, turn pumps on and set sump level. Done.
i have a small sump so just unplug the pump and let it fill the sump... then i top off the sump and drain the tank.. then fill back up to the bottom of the overflow.. and turn the pump back on after that..