Just put your siphon tube into both sides of the overflow (inside and outside box). An air bubble will form at the highest point of the arc at the top of the tube. Push a section of airline into the sipon tube up to the highest part of the arc. Suck the air out of the siphon tube being careful to stop before getting a mouthful of tasty aquarium water! Once the siphon starts, don't worry if a small air bubble is left dancing around at the top of the siphon tube. It will go away on it's own in a short time.
You might also want to check to make sure that you've got a small hole just above the water line in your tube or hose running from your return pump. The hole will let air in preventing a siphon from forming in a power outage. Without that little hole, you risk a major flood!
Good luck!
You might also want to check to make sure that you've got a small hole just above the water line in your tube or hose running from your return pump. The hole will let air in preventing a siphon from forming in a power outage. Without that little hole, you risk a major flood!
Good luck!
