That's what I thought. I pretty much just have this algae now which I'm fairly sure is BGA as nothing is eating it and you know, it's blue green in color.Hi @mrhoyo
As you will see from the link provided in post #1, your figures above would put you in the 'chance of green algae' zone. But, you say you have BGA. So, something doesn't tally. I am aware that the API Nitrate kit has had its fair share of criticism but I don't think it's likely to be reading 1000X too high (nitrate would have to be 0.01 mg/l to bring it into the blue zone).