I hope I don't sound argumentative, because it is not what is intended. But, I'm not sure if you can tell if you're cycled if you can't test for chemicals. I would guess it is a bloom and that you have not completed your cycle. However, that is just a guess without knowing what your levels are.
I would suggest grabbing (at a minimum) some test strips or (better) something like an API Master Kit so you can test your levels in the tank.
You can turn the lights off and perform a partial water change, and then maybe repeat the water change every day until you get cleared up if it's a bloom. But, it would be (somewhat) normal to have an algae bloom as your tank completes cycling and can clear up naturally.