We timed just how long it took for every air pump to vacant a liter of water in the bottle. Given that a liter of air displaces a liter of water, this gave us our movement fee in liters per minute (LPM), which we then converted to gallons per hour.I've a 220 L tank 900mm prolonged, 500mm higher and 400mm deep. I would like to run a sponge filter an… Read More