Tips on solving Hydra blow turning off

Since the Hydra blow is an only damage source of Hydra, maintaining the blow is a key factor for Hydra. However, some ppl mightve realized Hydra blow turns off when you let it stand in challenge top. This is because your character cant manage the increased mana cost of Hydra blow. Even with the mana restoration passive, blow can be easily turned off when the mana cost stacks up 3000 or even 4000%.

What I did to solve this is maxing the reduced mana consumption stat. After I maxed out this stat, I havent seen Hydra losing blow and stacks unless the character actually dies. Armor's spell option has this stat. Also, either pet option or additional stat at character selection page can be a good source.