Dropped tiny screw in tank.

[Knucker]

Just leave the silly screw in there and go out to breakfast. Try the pancakes. I have so many screws in my tank I could build a 1957 Oldsmobile out of them and my tank is running almost 50 years. I built half my "rock" out of screws and threaded rod. This hobby is not very hard but we make it sound difficult with all this worrying.
My thermometer is also stainless steel
If my copperband had thumbs he would straighten out that can

I love the beer can. It adds a bit of realistic feel to the tank.

 

[Knucker]

So i was taking a light off my aquatic life hybrid fixture and dropped one of the tiny screws that hold the led mounts in place. pretty sure it fell into a hole or crack in my rock work. Out of the 4 screws, 1 is magnetic, and the other 2 are not. No idea what they are made of. What would you do?

Well from what I know GFO is Granulated ferric oxide or rust powder, so any Iron or Steel is fine. You could try to use a turkey baster and blast any cracks in your rockwork. It might knock something loose.