I just finished cycling mine. I waited until all Ammonia and Nitrites were at 0 and all converted to Nitrates. Then I did a huge water change. High nitrates and phosphates will just give the algae fuel. I made the mistake of not quickly doing a water change and had a hair algae explosion almost over night.
But then again, I accelerated things by adding pure Ammonia to the system instead of a gradual ramp up.
My ammonia hit zero first then a couple days later is when the Nitrites hit zero. I think if you keep an eye on those you will know when to water change.
Oh, and I flipped the UV on once the algae started.