In a tank where the nutrients in the water are out of whack, a bacteria like Cyano can thrive. The most successful ways of dealing with it I've seen have involved plants and ferts, the problem being that most of us don't know what minerals we have in our water. I used very small doses of Potassium Nitrate to control it at my old house, til I couldn't get the stuff because it is used in explosive making by the US militia terrorist groups. That was a suggestion from a very old fishkeeper, and it impressed me. After the supply issues kicked in, i use a 3 to 5 day total blackout, towel over the tank to derail it now. In my new house, it doesn't expand quickly, and just kind of sits there in one or two spots. I hope that's what you'll see.
I found it went crazy in tanks with water wisteria plants - they must have consumed minerals that suppressed it, because invariably, if they went in they were Cyano coated within days. But in my new environment, post move, I could probably grow them with no problem. It's an organism, possibly the original one, and it's tough. What works for me may not work for you.
I didn't take those chemistry courses I should have.