Jep, I'm in a 50 hz country... so there is about 17% performence loss here... (but the pumps should run a bit more silent over here

)
And you are right, there
should not be a problem....
but if there is..
It will take me about 2 weeks to get a replacement.
2 weeks the computer down is not an option for me. So I go for safe. Depending on how it performs, it could be that I'll be running just one pump, and have the other on spare, or run the pumps at a lower voltage.