NChad you see that was easy to figure out. For some reason I don't think the zoo stunt a % just die off or are grazed by fish and bugs. Same for phyto there #s vary based on many factors like water quality , zoo #s (all predation from zoo to TShad/grazers), light and nutrients . If the water quality and temps allow and when predation reduces then the phyto #s jump and its green again. As long as you have ray (light) and wettie (water) and nutrients (soil) something will fill the void with life. Life is the epiphany. \:\)