nano tank build

i got this coral like a few weeks ago everything was good until i did a slight water change and added new salt the next day i woke up it looked like it had white algae and some parts look fine. should i remove it from my tank or leave it there and see what happens? will the dead/dying coral...

I started a my 10 gallon reef tank about a month ago a started it off by adding the sand, water then turning on the pump then added two pieces of live rock. I waited about a week then added my first coral (which was a Xenia). Later that week I added a clownfish, and then another week passed...