Response From Lance Shaner :
"OYL-500 (our hybrid strain) is a pure strain resulting from the mating of two other strains. Thus, it is can be harvested and re-used like any other pure strain. Because blends such as our 210, 211, 212, 217, and 218 have multiple strains, there could technically be population shift over time. Although, in the 210, 211, and 212 blends, the two Sacch strains are very similar, so any shifts in population may not be noticed from generation to generation. Hope this helps."