If there's enough surface area, there's plenty of biofilm.
For me, Jake's stix w/ Ca+ and bee pollen. Jake will be the first one to say use other foods besides his, but I must tell you that I have gotten the best results by using his products almost exclusively.
At first when I started feeding, my shrimp would NEVER eat anything except Fluval Shrimp food. After I got a good colony of 10 adults, 30 juveniles, and 50 babies, I fed them Azoo Growth and they swarmed it LIKE CRAZY! This happened just today. I've noticed the healthy ones attack it first and the others wait, but they attack it furiously and specks of the food fly out for the babies to eat. My shrimp don't like it when I put the food on a feeding plate too. I don't know why, but they just don't. I feed mine Azoo Breed,Growth,Color, BW Barley, BW color, Shikaria (don't know how to spell) Soft taste, Jake's om om om food, and Fluval Shrimp pellets. (Got these goodies from all you great people here)When you have a small colony, few adults, I recommend feeding Fluval food because they usually finish it off faster, and it's unlikely to overfeed with such a small amount. Good Luck!