I have a brown hair algae that is growing on the fleshy part of a paly coral and another on the fleshy part of a kenya tree. Is it possible for hair algae to take root on the fleshy part of a coral? It wouldn't be dinos would it?
Your DT looks very young your sys is going thu the GHA ugly phase, yes that algae will get on everything, its best to avoid any corals till the DT stabilizes, go fish first, then soft corals next, then hard corals even later once fully matured... which can take months and even long as a yr sometimes or longer depending on sys. bio load and setup.
It will slowly clear up IF you can get nutrient export higher then nutrient inport.
It's not uncommon for algae to grow on the bases/stalks of polyps and leather corals. You can easily (& gently) siphon it off with water changes. Corals are essential for the carbon, nitrogen and phosphorus cycles in reef systems and adding animals with robust immune systems like you've done is what I always do as quickly as possible.
Tank has been running about 2.5 years but moved 6 months ago. The person I purchased it from about 6 months ago had cheap aqueon lights (fowlr) which I imagine is the cause of the lack in coraline algae. Currently have a kessil ap700