Stability of Frequency in Hydroelectric Mining setups

Trying to set up a hydro system for mining. I think the generated frequency (like 60hz) might not be super stable... could that fry my S19 miners?

How much fluctuation are we talking about? Best to design your setup within the power supply specs... I mean, it says 47hz to 63hz should be okay.

I've got a thought. Why not turn the AC output from your generator into pure DC and then back to 220v AC? That way you can nail the frequency down better.

I remember reading about this dude online who managed +/- 3hz using an Arduino to control the water flow into the turbine.