Solution for my aquarium

[Porcupine Reefer]

I haven't done an update on my 125 gallon tank in a long time, but now I need help for my tank. By accident I added tap water from my sink and as a result I have a massive outbreak of hair algae and cyanobacteria. I treated the tank before with chemi clean and not only did the cyanobacteria come back, but my blue tang was really stressed from that entire process, all the other fish are fine, but I want to fix this tank. One of my local fish stores suggests to do a 25 percent water change daily for 6 days straight, but will that be effective? I'll appreciate any advice anyone here can give me.

 

[JumboShrimp]

How much tap water do you estimated got added? Municipal water (not private well), is what I assume you mean by "tap". Either way, the adage is: "When the problem is pollution, the remedy is dilution." So water changes might be a good start; but too much, too fast, might cause its own problems for your corals.