If you aren't moving at a snail's pace, you aren't moving at all. -Iris Murdoch
Surprise, we're super interested in this because we're trying to figure out how to catch water/media samples at our Em4 model's drain and then convert things to dry sediment discharge rate! I think a semi-wet measurement would work if we could standardize it somehow.
The question is, do you want to sample continuously, or just periodic "point" measurements? Would a column of water with plastic fragments falling through it register a higher SG using a hydrometer?
I don't understand what you did.
I'll be expanding the specific gravity of sand description tomorrow. I'll have some pictures.
A little more info here: http://pascals-puppy.blogspot.com/2011/02/specific-gravity.html