Thought I should try the Tortoise in edenhall. Actually killed him, took me about 25 mins, but I won

So I figured about 20 to 30 mins to kill one of these is a good way of farming the goods. Turns out the turtle in Gran Pulse is easier and gives exactly the same drops/cp O_o. Took him on through the mission and downed him in under 3 mins got a nice 5 star rating and a Genji Glove (didn't know that was one of the missions for the glove). Thinking, awesome this is even easier to farm. So I did the mission over (one turtle for the mission and there are two other turtles on the sides giving me a total of 3 turtles with about 40k cp per at 2 to 7 mins per battle plus the mission automatically gives your a gold nugget which sells for 60k gil. On top of this I got 2 x platinum ingots and a trapz ore) and find this is a great way of farming. So I can take down about 3 x turtles and 1 x tortoise in about 15 to 20 mins. Yayaya
Had the post it as I was excited as hell to be able to take these things down. However, I can't for the life of me kill the Gigatuar. Anyone have any clues on this giant cactuar? I get to almost 60k life left and my healer esuna's me instead of healing me.... Any tips would be helpful. I'm trying not to youtube the video and read a few strat guides.