Can college students get the ACA tax credit if they earn less then the Federal Poverty Level(do they get part or none?)

 
What happens if  2 college students don't earn the minimum income requirement(100% of Fed Poverty Level) for the ACA tax credit? 
...Do they lose the credit entirely and have to pay ALL of the advance back or just part of it , or none of it?

...They each file their own tax returns and aren't claimed as a dependent by a parent

...each gets insurance from the Market Place, each take the $280 advance credit

...one student only makes $10,000 for the year 

...other student doesn't work at all but has $1800 in interest income)

I'm wondering what happens at the end of the year when they file their respective tax returns. Any help would be appreciated.