I just bought an Aquabot Mambo suction cleaner. As soon as I connect it to the skimmer, I get air in the line. I disconnected the hose from the cleaner while keeping both the hose and the cleaner submerged. Our self priming pump filled up with water again. As soon as I connected the hose back to the cleaner, I got air in the line again. Is this normal? Is it ok to have some air in the line or is that harmful to the pump? I'm a new pool owner and I'm still learning. Thank you.