More on my salinometer quests! (Mind you, I'm working in a summer camp, so I don't get a lot of free time, but this is what I worked on.)
I tried this new method of what I call "bottle buoyancy". (I can't really explain this - I just watched this video and made something similar: http://www.youtube.com/watch?v=-wfL1kVtmvM
I calculated the flow rates for several different salinities, and most results came out to be pretty similar in the time it took for the bottle to fall. I kinda found a relationship of my own, and I was able to get pretty close for a random salinity! It does look like a swell design, but a few results were a bit skewed, plus I'm not sure if judges would allow us to bring in stopwatches.