air in pump

[Poconos]

Barry,
Welcome to the forum. Don't know what that fountain attachment looks like but if it extends above the waterline somewhat that could account for some backward surge when you kill the pump. The water in the fountain pipe drains back to pool water level. This should not cause any air to get into the system though. Usually when the pump basket drains and gets air in it, that is an indication of an air leak on the return side which is usually the filter valve. If the valve doesn't seat properly the waste port can be open a little and let air back into the system when the pump is off. Is there a trickle of water out the waste line when the pump is running? If there is that indicates where the problem lies. If not, that doesn't mean air can't be leaking from the waste port when the pump is off. Doesn't take a very big opening for a significant air leak compared to something allowing water to leak.
Al

[Barry J]

I believe I fixed the leak with some teflon tape...but, my return hose does some vibrating which cause that fountain to vibrqate...any reason why my return hose vibrates...is it too long maybe???
Barry

[Poconos]

Barry,
One possibility with the vibrating hose is it could be resonating. Everything that can flex will have some natural frequency and normal water flow through a flexible hose can start and maintain oscillation. If there is no air coming out of the return I would guess this to be the case. A resonance would cause it to vibrate at one frequency and the vibration would be regular and not erratic. If it isn't vibrating enough to cause a problem like eventual fatigue of a joint then I'd just live with it. Shortening the hose may help. Best I can do for now.
Al