The only way to get rid of the hair algae is to get to the root of the problem(s) and fix them. Here's a quick list of things you'll want to do.
1. Only use ro or ro/di water for water changes and top off's
2. Cut back on feedings by at least 1/3 or more.
3. Make sure to do weekly water changes of 25%
4. Pull out as much of the hair algae as possible
5. Do a blackout period with no lighting for 3-4 days followed by an immediate 25% water change. Then slowly increase your lighting back to the normal schedule.
6. Continue normal water changes and monitor all tank params closely for any changes.
7. Make sure you have fresh light bulbs as old bulbs can cause algae to grow.
That's my advise in a nutshell. Good luck!
Also, read this thread and it will help you.
https://www.livingreefs.com/great-algae-genocide-war-2010-a-t24202.html