Alot of times algae can actually be caused by lack of fertilizers. I would get on the Estimated index fert dosing plan, that would be your best bet to balance everything out. I would lower lighting period to about 7 hours for a few weeks while everything adjusts. Just make sure you do a solid %50 WC every week. I know you've had issues with Ferts, but I'm telling you perserverance and cosistancy are the best things in this hobby. If you being dosing EI method, and doing a single 50% WC every week, you will be golden. I know its not a very quick method. But this isn't a really quick hobby.