Tower #3

Level 1, cost = 1500 crystals, yield = 2.88%

Level 2, cost = 2250 crystals, yield = 2.90%

Level 3, cost = 3375 crystals, yield = 2.94%

Level 4, cost = 5100 crystals, yield = 2.95%

Level 5, cost = 7650 crystals, yield = 2.992%

Level 6, cost = 11470 crystals, yield = 3.01%