Looking at that picture, the water is very clear, but that isn't Sago in the picture, now, is it? I believe that the pond saw an influx of nutrients, coupled with better water clarity, which combined to produce the increased Sago growth. The growth didn't happpen the following year due to a reduction in available nutrients, reduction in water clarity, or a combination of both. Probably due to the amount of water flowing thru the pond.
