6015 Magnets not covered?

[GiantBen]

I have a Tunze 6015 and just got another one. One the one I just got, the magnet holder doesn't have the rubber seal over the magnets. To put it another way, the magnets are exposed. Is this a danger to be submerged in the tank?

 

[rvitko]

The 6015 used to include a neodymium magnet holder, neodymium will corrode and must be coated, they were coated by polyurethane in the old magnet holder. Since Neodymium's sole source is China and China nationalized the mines last year and the price went up 600% at its peak, we switched to Ferrite, Ferrite does not corrode, it is the grey magnet material most impellers are made out of and it is not coated, since it is a weaker magnet the holder must be filled with much more ferrite than we needed of neodymium.