An update: I started using Biofine about 5 weeks ago. When the beer was ready to transfer to the keg (at basement temps), I injected about 30ml of Biofine into the tubing prior to starting the transfer. The Biofine would hit the bottom of the keg and the beer would be transferred on top, mixing well with the beer. Every one of the beers I sampled where I used Biofine is really, really cloudy. One of those kegs is about half full. Another has had about 10 beers tapped from it. Others have been sampled with a cobra tap. Can anyone see a scientific reason why the Biofine would not work? Something in my water or something with my processes? I am in the process of making a big batch of gel solution to see if I can clear these kegs up. I tried a similar Biofine-like product years ago and had the same results. Cheers guys.
Most fining agents work by pulling "stuff" out of suspension via relatively weak electrostatic attractions. At room temp, there is a lot of kinetic energy in the beer molecules, and the stuff is zipping around so quickly that it overcomes the attraction. Slow the stuff down, and it'll bind. Chilling slows it down. This is why you should only fine after cold-crashing.
The amount of biofine to use to clear a beer is very much dependent on the individual beer. For a given beer, the right way to use biofine is to do trials using small samples of that beer and different amounts of biofine, to see which amount works best. Sounds like a PITA? It is. Which is why no one does this. But this could explain your lack of results.
The king of fining agents is still gelatin, AFAIC. Sorry, vegans.