Major algae during fishless cycle

[Aquafriend]

Well, numbers are down again this morning, but without any water changes this time.
ammonia 0, nitrite 0.3, nitrate 20, PH 7. I'll dose in a little while, then retest a couple times over the next 24 hr to see what it's doing.
It's encouraging that the numbers came down alone during the night.

 

[Aquafriend]

Today when I came home from work, the numbers looked lovely .

I'll still give it a couple days, just to make sure. The nitrate is down, too, (less than 20), but I have green algae from all the high nitrates I had. Can I just clean it off, let the filter suck it up, then rinse the foams in a bucket of tank water to clear them? It's stuck all over my live plants, as well as everything else. Even though the nitrates are down, I'm still going to do a big water change before adding fish.