I had an algae bloom on the 2nd day after filling my tank. I don't have any direct sunlight & left the light on 4-5 hours, maybe, IDK--haven't turned the lights on since!! I didn't have any plants, EVERYTHING was brand new, no seeded media. I blacked the tank out 3 or so days before beginning my Fishless cycle. I am still doing a Fishless cycle & I have a minor bloom now. I've changed the water 2x since the beginning & it gets very clear, then slowly comes back, it hasn't gotten as bad as the first time. Just thought I'd share my algae bloom experience w/ you. I have not tried any algae removal products. I have heard it's* not harmful to the fish (don't quote me though!!) and there are **diatomic filters that help remove the algae bloom* (again, don't quote me... but it's a start of where you can go from to try to solve the problem). Oh, and algae love phosphates, could your water source be high in phosphates?? I used Spring Water the first time filling my tank & come to find out, that particular brand is drawn from close to phosphate mines! YIKES!! So I use tap city water now but I think once the algae bloom is there, it takes awhile to get it out.
*heard the Algae Bloom is not harmful to the fish
**EDIT: So they're not diatoms but I've read diatomic filters will help remove the algae bloom--might not be true though!