I've heard that they are too cheap cause the regenerate is too much, maybe just try to control it with the timing and amount of it.
IRON Regenerate :
Level 1 = 5 Seconds, 1 Iron(s)
Level 2 = 5 Seconds, 2 Irons
Level 3 = 4 Seconds, 2 Irons
Level 4 = 4 Seconds, 3 Irons
Level 5 = 3 Seconds, 4...