What are you running salinity at now?
Ive pondered why most LFs and some people who run fowler keep fish in lower salinites then nature that animals have evolved in for millions of years?
I always try to keep all my tanks at NSW levels (1.026sg or 35ppt salinity) regardless if fish only or combo . I think most lfs who run lower salinities do so to simply save on salt or since lower salinity water carries more oxygen less need for more aeration pumps/skimmers etc. Skimmers underperform and do not work as well in low salinity hence why their not common in freshwater tanks unless only to be used as an expensive air stone. To be even remotely effective against parasites, you need to be in actual hyposalinity, and then you're looking at levels of 1.009sg/14 ppt salinity or around there from what I’ve read. At times I run 1.025 on smaller tanks I set up temporary that I manually top off to give me a little buffer zone and or if a friends popping over to top of a tank when Im outa town. Anyway sorry for the salinity rant!!
Your not alone on here with misdiagnosing algae/bacteria with high blues on and certainly won’t be the last lol. Chemiclean may just be a bandaid until you figure it out or nature does. It’s an antibiotic which kills bacteria the bad and good stuff. We cant underestimate the benefits of many different types of good bacteria the more the better in our systems. Get some extra power heads on your rocks and sand to help with cyano and keep up with manual removal brushing rocks!
Long hours with any light will increase algae growth unless you have strong cucs and herbivores but thats not a definite. Less food several times a day vs larger feedings have really made a huge difference in my fish mowing algea. Even the other fish besides the tangs that normally never eat algae jumped on the bandwagon.
Best of luck