I see the status of the drives as non critical

i think this is a predictive failure. is it required to replace both the harddrives or is there any alternate solution for this.

I got one drive replaced which was a perfect failure and the other is in predictive failure, when i replaced this drive again the drive which is replaced is back to the non critical status. Does the raid affect this in any way..?

Please help me with the solution other than replacing the hard drives.