Recognizing that a set pairs nicely with your class's unique talents--in this case, consuming potions--is the first step towards mastering combat. Yes, Arkasis can be used on tanks. Nightblade or otherwise is acceptable. Look into Drake's Rush as well for a different flavor of ultimate regen for your group.
/script JumpToHouse("@Paramedicus")↑↑↑ Feel free to visit my house if you need to use Transmute Station or Trial Dummy with buffs (look for Harrowing Reaper) ↑↑↑