Full transparency - I was alluding to the fact that you may be using tap water, with my fingers crossed that you would tell me "PSH No way Jose!" Your hair algae issue is quite possibly fueled by tap water if it contains nitrates and phosphates. Have you ever asked your LFS if they use tap water for their saltwater tanks? If so, acknowledge how their tanks look. If they're great, then ask what they're doing to the water to keep it in check. If they're not great, then that's an answer in itself.
I hope you will consider distilled in the mean time, until you're up for either buying ro/di water or making your own via ro/di system. Check in on this thread for more info:
https://www.reef2reef.com/threads/how-many-of-you-is-not-using-rodi.789298/
Surface aeration and agitation is very important, especially as your only source of overturn for O2 - but I do not have enough knowledge to tell you whether or not it has any impact on nitrates. Once a skimmer is in place, that'll provide ample amounts of oxygenation alongside the reduction of nitrates ten fold, but not as beneficial as using ro/di.
You can either create new saltwater with the highest confidence of 0 nitrates and 0 phosphates using Ro/di
or
You can create new saltwater with unknown nitrates and unknown phosphates using tap, with hopes of removing them with chemicals or compounds like GFO and Carbon and have a never-ending battle