I have the Tunze nano ATO and I have a weird issue with the pump. I have gone thru 3 pumps already and it is always the same issue. New, It will pump water no problem up about 4 ft for a month or 2 then all of a sudden just lose most all pressure. I run the water clean, no kalk, never runs dry, and the hose is completely clear. the float works fine also. When I take the hose down to just above the ATO tank, water flows. I raise it up and it stops. so what the heck? Anyone else have this happen?? anyone know a fix, or how to use a different pump without having to use like plug adapters?