FluvalInput Shaft for FX6 Filter

Okay so we only set up our FX4 in September 2019. Within months we have had a connectivity issue in the shaft input and bought a spare (even though by appearance nothing looks wrong). Over time what happens if you are taking it apart regularly to clean/maintain, because it is in two parts and the way it is held together the initial tight connection you get between them goes and so does the flow rate. We noticed that the strainer suction was poor and whenever we were draining water change via the utility valve, it began completely loosing suction and drained the pipe when the water level reached the top of the first shaft part where the second adjustable piece fits onto. Theoretically you would expect the suction to pull in water through the strainer at the bottom, this isn't the case.This is a part that will need replacing regularly due to minimal wear and tear. The replacement part is completely fine and perfect, however it is poorly designed and we are looking for better permanent replacements without compromising flow rate.