Just keep up on the changes, the blackout is a quick fix, the underlying cause will still need to be addressed. With FO tanks, I always found algea close to impossible to control at all times. The blackout trick was always part of my maintenance plan when needed to set things back to right. Snails are another good helper with algea, but depending on your fish they are sometimes inpossible to keep. I have had green water in more than one FO tank that was quite healthy otherwise. the first time, I did daily water changes for more than a month, before someone told me to black the tank out. Every day the algea would get thick by the time I came home from work, and then I'd thin it back down with a water change so it could grow again the next day. Lesson learned and then driven home years ago.
dave