Those pumps last years using regular aquarium stones. Now sanitizing those type of stones may be an issue. For one, I read they can't be boiled, they'll disintegrate.
But after use, they can be rinsed then soaked in Starsan for some time, say an hour, so all channels and pores get sanitized. Perhaps pumping some Starsan through them may work better.
There are many other ways to aerate/oxygenate, one of those spray cones, whisking, pouring back and forth between buckets, etc. Only higher gravity ales seem to benefit most from higher ppms of O2.