I think the inner material in the bag would be much more productive if the material was in sheets or layers 2"-4" thick instead of 8" dia cylinders. This would allow optimum water flow among the substrates. In thinner layers would also allow small fish to feed more effectively on more of the surface areas rather than primarily on just the cylinder's outer walls. Set up as layers would also provide more cover/habitat for small fish.
I would like to see data as to the amount of nutrient absorption there is per cylindrical bag compared to thinner layered 'feeders". This sounds like a good senior or thesis project for a student subsidized by the Jesse West Foundation and "FISHIDING".
