What are your water chemistry levels, ie: NH3, NO2, NO3, PO4, pH, and so on?
The potential cause(s), will depend on your water chemistry, lighting, fertilizer dosing. You will need to try to find the cause or, yes, it will come back. NH3, high NO3, high PO4, and/or excessive light with the abnormal chemistry levels. If you are running high light, decrease the amount of light and then try to find you problem first, then proceed.
Once you know your water chemistry are all at acceptable levels, then a blackout can work. But if it doesn't, some overdosing on Excel has worked well for me. I have had major headaches with green algae and green water, and will be more than happy to try to help. Eventually, I bought an other pump and added a UV light filter. Now my tank is looking fantastic with crystal clear water - knock on wood.
I can definately tell you something NOT to do. That is add chemicals such as "Algae Fix" I had a horrible time after using that and it was recommended by a local fish store.
Check all your water chemistry levels and post them. We can all go from there. The people here are great and offer great and helpful advice.
Good luck!!!