From what I gathered watching the live stream with Luis from Easy Reefs, is that EasyBooster is phytoplankton and SPS Evo is zooplankton, which also contains different phytoplankton as well (I could be wrong with my info?). Sps will directly and indirectly feed from them and are a complete food source for sps (per Luis from Easy Reefs). All I can say is that it's working for my sps/tank. The overall health and growth of my sps has increased after dosing both. Is it a direct result of dosing both, I can't say for sure, but I'm going with 99.9%. Will it be the same in other tanks? Like many things in this hobby, it's uncertain, but I'm pretty confident there are benefits to dosing both and there's no down side at this moment. The 250mL bags are relatively inexpensive, so it was worth a try and I'm glad I spent the money.