1, depending on what type of motor you use, is the power supply 220V, if it is and there is a starting capacitor on the motor, it is likely to be the starting capacitor aging resulting in a smaller capacity, replace a slightly larger capacitor, if not, you can refer to the upstairs wirelessThe method said by the electric industry.
2, both. General wave pumps are front blowing, back and side suction.
3, I have also encountered the same problem in normal work, but when the pump reverses, the pressure of the pump is slightly lower than the pressure during normal operation, and once the outlet valve is opened, the pressure drops instantaneously to a lower level. When reversed, the impeller will also work on the liquid, generating centrifugal force, but the liquid will produce turbulent flow in the impeller channel, friction increases, and useful work is reduced.
4, the normal water flow will not cause the fish to sleep, and the flow rate in the field river is basically unchanged. My 120/