Everyone has their own methods that work for them. If I'm NOT harvesting the rotifers at the moment, I use nannochloropsis when I have enough because there is less fouling of the water, but, when I don't have enough nanno, then I use spirulina powder blended in a blender for at least two minutes and then stored in a pop bottle in the fridge. If I'm harvesting for use, I want the best nutrition possible so I use the blended powdered spirulina AND add powdered Algamac 3050 (really high DHA) to the mix. IMO, a single live phyto will not provide the best nutrient profile, but spirulina is an excellent source especially with the Algamac 3050 added to it. The downside of the powders is more frequent cleaning of the culture vessels. I forgot to add, I start with the water quite dark when using the phyto but less so when using the powders, preferring more frequent addition for the powder because the powder is harder to keep in suspension.