Are those metal valves? Curious if the are reef safe.
You had me a little worried if in my gate valve was metal or not I had never even considered if the part in contact with water is metal so I had to do a little more research.. looks like the only part on the gate valve that's metal is screw holding the wheel on.. at least that's the only thing that a magnet will stick to.. the actual knob may be aluminum it's non magnetic and coated so not to concerned about that.
here is a picture of the valve stem and the actual valve from the outlet side..
Hopefully nothing to worry about



