Honestly I would not stack the two of them. You are definitely better off with essentials, reason being that essentials provides all vitamins and minerals needed just like poseidon, Plus we incorporate creatine monohydrate which increases ATP production allowing you to get more reps and strength in the gym. Beta-alanine also is a great addition to essentials. It increases aerobic and anaerobic endurance through increasing carsonine levels. Carsonine levels aka fast-twitch muscle fibers are important to all athletes and bodybuilders looking to put on lean muscle mass and explosive strength. Essentials also contains all BCAA's needed which is an important aspect to recovery of the muscles, let's not forget about the digestive enzymes which help you digest the compounds to essentials easier, which means no GI-stress, eventually meaning more bio-availability.