Welcome razorstorm 
  This has come up before a few Times ...... frustratingly with different fixes! .... here's the ones I remember from memory in no particular order to trouble shoot..... the top 2 would be most likely 

  Bad/cheap Sata Data cables causing SMART threshold to be exceeded ....Fix....better quality cable
  Insufficiency gap between Sata data and power cables re cable management....fix....minimum 3 to 5mm gap where possible or sheid
  Disconnect the power and Bus of hard disk and reconnect.......this will let you reboot your computer without any issue and back to booting menu but again only a temporary fix from what you explained.
  Turn off SMART Response in Bios........... (not a long term fix but good for trouble shooting)
  Failed drives.......fix......RMA.......probably not applicable in your case but still possible.
  Flash firmware of SSDs to latest Version
  If everything else fails above......drivers and motherboard comes into the picture
  Aussie Allan