Servicing Air pump

[Stones]

Out in the garden yesterday, I immediately picked up on the absence of background noise from our treatment plant air pump.  On investigating, found it was dead and had to swap it over with a spare that I have.  On opening it up to determine what the problem was, I found the wires to the alarm warning light had somehow shorted, and that the plate linking the two diaphragms was to all intents and purposes magnetically attached to the left hand coil.  Having safely terminated the alarm wire lights, I took the diaphragms off, cleaned and refitted, and the pump is once again working, but as you can see from the image below, the connecting plate between the coils is not centred, and I'm guessing it wouldn't take very long in terms of operating hours for it to come to a halt again.  I have a new set of diaphragms which I can fit (guessing this is the issue), however as I'm not going to be using this pump for a while (this pump will now become my spare), would I be better advised to leave the new diaphragms in their vacuum sealed pack and replace as and when I need to fit this spare?  It's only a 5 minute job so not really a concern time wise, more a question of deterioration in new diaphragms if not being used.