Personally, I'd do 15 gallon water change every other day for 8 days (a total of 4 water changes). This will get your nitrates down to the teens and then you can go after your phosphates to get them under .1ppm. You can use 4 more water changes every other day, gfo (GO SLOW), or phosphateRX (my favorite). You should review how much you feed and how much you water change based on how your parameters go weekly from there. You rocks will leach nitrates and phosphates for a while, but after keeping your nitrates and phosphates down for a while, the hair algae problem will go away. Also while doing this, keep manually removing the algaeI added a skimmer and been doing weekly 10% water changes