Allan from John Allan Aquariums, at MY house!! What a lovely guy.
He came to help with Eheim 2217 Classic because it's been noisy and he was passing my house (lucky me!) well we tried 3 motorheads and it didn't make a different, we ended up turning the outflow tap down, he said he'd never heard that noise before, a sort of whistling grinding sound, so we figured the 2217 was too highly rated for a 250 litre aquarium and he said as long as we keep the intake taps fully open, you can have the outflow as low as you need it to be, it's certainly helped. What a great experience for me!
Gee mermaid... now that was disappointing... never heard of the guy.... I thought you're talking Dr. Herbert Axlerod (or William T Innes)...... Now THAT is aquatic royalty!!