I'm in the middle of a cyano bloom, it's getting worse daily. It started after I did a water change and the following week I cleaned out the sump. I did a water change 3 weeks ago, went well. Nitrates went from 15 to 10. I then cleaned the sump and nitrates have dropped like crazy and the cyano is building fast. Last week nitrates were at 7, cool. This week 2.9. I dosed back up to 10ppm with some sodium nitrates. Corals overall seem happy but today the cyano really took over. Besides 'wait it out', I was considering doing a chemiclean treatment in a week or so along w another water change. Is it fairly common to get cyano in an established tank? It's pretty bad. Like uglies bad lol.