TNG
Fishaholic
The diaphragm works to push air through the tube or through the valves, but it needs very little energy for that (outside the tank where there’s no water in the tube).
When the pump is off, there’s water in part of the tube inside the tank. When the pump is on, the diaphragm will work hard to push water out of the tube and to get air out from the air stone, and it keeps working hard to keep the water out. Much of back pressure is the work to keep water out of the tube inside the tank, the deeper the tank the higher the pressure.
When the pump is off, there’s water in part of the tube inside the tank. When the pump is on, the diaphragm will work hard to push water out of the tube and to get air out from the air stone, and it keeps working hard to keep the water out. Much of back pressure is the work to keep water out of the tube inside the tank, the deeper the tank the higher the pressure.