That's a good question mate.
From what I understand, not all that much if you are trying to capture very fine gold.
Basically I believe that you are relying on the weight difference and viscosity difference for the gold to fall out of suspension. With dirty water the capture rate goes down.
But I guess if it makes the difference between running or not, I would probably give it a go.
Maybe take a video of what you are doing and ask again, it's difficult to say without seeing anything.
I did that a little while ago myself. I found it disconcerting as I couldn't see any exchange as it was just too muddy, but I did bring home gold, so it still worked to some degree. How much was lost? I'll never know.
