[sde1500]

Yes if the color darkens a lot, it is growing well. And actually in my experience, nanno being non-motile does not make a good food source for my pod cultures. I would use it and the water would stay green, indicating they weren't eating it, plus there is a slightly hard shell around the nanno cells that pods struggle with. Tetraselmis is another phytoplankton, motile and with less of a outer shell, making it a better food.