Cyanobacteria are a whole different situation. I don't count them as algae as they aren't algae and you wrote those are dealt with. I was referring to the other stuff. Sorry.blue green algae
Clearwater also has some humic substances, not a problem. It is chemically still closer to blackwater than to european tapwater. And even with pure RO it would take a while and a lot to take any effect on waterchemistry. They are beneficial nonetheless.I just thought since borellii’s are clear water fish i should try to not get too many tannins, i added purigen in my filter too.