There's only one quest acctualy to farm Elemental rep. It's "Help Professor Warlic", and it's a pain to farm.
My advice: Wait until friday, because AE is going to release another quest to farm, maybe a lot easier.
It you still want to farm on this quest, it would take more than 3 full botting days to reach lv 6.
That's a bot for example:
https://www.mpgh.net/forum/219-aq-wor...ion-bot-*****ml