listen....I don't think pet stores are generally "great" as sources of information, I used to work in the nicest salt water Aquarium shop in the Mass/conn/RI area....and even there there were people that would give bad advice....bottom line is it is a business, they need to sell you stuff to stay open...if you buy the tang then it will fuel the algae problem...no matter what kind of algae it is. Then you come back to them and they will sell you some algae remover...which wont work...then finally they will sell you an RO unit...why would we mislead you....there are like 10 people here telling you what it is, we have all seen it before, you havent, and you never know how knowledgeable the guys at the pet store are, I have met some complete idiots when it comes to salt water...and they work in "reputable" fish stores....Take our advice or not, it is up to you....stop trying to refute what we are telling you...you have algae, our advice will help get rid of it...and another thing, I have never heard of a "common" red algae bloom, just a heads up.