Thanks for the feedback. I'll definitely try out your recommendations and adjust the guide. It's my first one so any other feedback is greatly appreciated. :)

Manamune costs way to much gold for an item that only benifits yourself so it isn't good on supports.You should also get wealth so you can get a vision ward at level 1 instead of all of those health pots.Getting sheen instead of manamune would be good and i think you should get shurelya's reverie a lot earlier and maybe get an aegis of the legion

i advise against manamune generally, especially as support, it costs too much for a 100% selfish item, if you wanna get a cheap selfish item that gives mana, sheen would be a far far better choice, that would increase your damage by a comparable amount, and also the less money spent on yourself the better, you're a support tank after all.