zuk 50k damage problem

i have 99 stats with elder overloads salve, curses, essence of finality, tokkul-zo ring and obsidian mage helmet, cryptbloom top and bottom with perks (crackling 5, relentless 4, devoted 4 and enhanced devoted 4), praesul wand with precise 6, malevolant kiteshield, ancient book with ultimate 4 for off hand dps, essence of finality and mej cape, kerapac gloves and blast diffusion boots and i still can't deal 50k at wave 4 with sunshine ability and exsanguinate 12% damage boost its so stupid