I just finished my task of # (the reason I put #, is because I spread them out so much, I don't know how many i was supposed to kill! LOL) harpie bug swarms, and went to Sumona for the first time, and she gave me a task of 160 dagannoth's, so i'm going to buy a cannon (I sold mine after I stopped slaying) and about 500 cannon balls. Any advice would be appreciated. Hope 500 cannon balls will be enough. check in my goals block at the side of the screen for my progress at my goals, mainly slayer.
EDIT: and thank you all who suggested i take 1k cannon balls! I'll do that!