User blog comment:Sethimothy/Omni Arcanum & The Sphere With Too Many Ingredients/@comment-26947994-20170910191110

Is it even possible to get the Tempest of Akachi without using gems?

Well, every day has 24 hours, and the event is open for 6 days (Sept 10 - Sept 15 inclusive), meaning that the event is open for 144 hours. Each hour gives 20 energy, so the total free energy gained is 2880 energy. Then, we will assume that we are only tackling the highest level dungeon because that level is the only one that drops Psychic Eye. That means every try takes 60 energy, so the total amount of times you can try the dungeon is 48 times.

Now, we factor in the initial energy. This depends on the summoner level, but for a level 999 summoner that had full energy (429) and was awake at 0:00 PST (like me), they would get to try the dungeon 7 more times, resulting in a total of 55 tries.

According to the wikia, the sphere needs 200 Psychic Eyes and 1425 total materials. This means that on average, F2P players should get about 4 Psychic Eyes and 22 other materials per run.

This is actually pretty impossible, so I hope Gumi/Alim/whoever created this has another way to get that sphere, because it looks like a really useful sphere... Please?