I'm not the best person to respond to this but here goes. I have been battling hair algae in my tank for a while now and have made some headway on it. I reduced my photo period back, eased up at feeding time, bought 4 oto's and started dosing excel 1.5 the normal dose. It's embedded in my HC but thats about it these days. I'm trying to find some amano shrimp to help. I also have a slight amount of phosphate in my source water. I'm working on correcting that but haven't as of yet. Those are a few things i have done maybe they might help you. I'm sure somebody else here will have more insightful info for you. Test your water also.