IMO the theory is very good, but the design is flawed. Floating islands succeed because the roots in the water column remain alive and growing with a loose weave with good water flow through the root matrix. The biofilm lives on the roots and small fish can hunt among the dangling roots. The roots and the biofilm absorb dissolved solids from the water. All key items for its success.
On the new bagged substrate design, the bag is packed too tightly with substrate, I think periphyton and associated invertebrates will live mostly on the outer or near outer surfaces. Most all the innner surfaces especially the subsurface and middle zones IMO will be wasted due to lack of water flow and over growth of the attached algae growths on the outer surfaces which are artificial. These surfaces will tend to readily clog and inhibit water movement throughout the bag.
In many waters that are plagued with filamentous algae, most of the growth on the bag will be FA which will create a mat on the outer surface. When that happens the inner matrix will receive too little light and too little water flow that will cause it to become unproductive and probably anoxic. How well this works in a pond will IMO be dependent on the nutrient regime in the pond. The nutrient composition in the pond will determine what grows on the bag surfaces.
I have done some stuff like this before and results were similar to those that I have described. If the material in the bag was spread out over a large area it would be much more productive and beneficial.
Last edited by Bill Cody; 02/02/13 08:58 PM.
