I've confirmed Liquidlife's Plankton Live is a single culture of Nannochloropsis sp. It's probably similiar to DT's old (less concentrated) formula.
I bought my DT and Liquidlife Bioplankton from www.marinedepot.com. When buying live plankton, I suggest you ask your retailer when they get fresh batches in. Also, inquire whether your dealer stores the DT in a refrigerator or not. Live plankton must be kept cool (<~55 degrees), while preserved plankton must be kept in the freezer.
I bought my DT and Liquidlife Bioplankton from www.marinedepot.com. When buying live plankton, I suggest you ask your retailer when they get fresh batches in. Also, inquire whether your dealer stores the DT in a refrigerator or not. Live plankton must be kept cool (<~55 degrees), while preserved plankton must be kept in the freezer.