I use the 'bitrot' app to store checksums of files and to check for bitrot. It works by checking for data changes that aren't accompanied with a file modification time change. With this you don't need something like RAID or ZFS or detect bitrot.
But of course you still need backups. The way to use 'bitrot' in combination with backups is that you don't backup the bitrot DB file. Instead, you run 'bitrot' separately on the main disk and the backup disk.
As for fire-proofing my data: I store a disk at an off-site location (parents' home), and I regularly swap my main disk with the backup disk.
https://github.com/ambv/bitrot
But of course you still need backups. The way to use 'bitrot' in combination with backups is that you don't backup the bitrot DB file. Instead, you run 'bitrot' separately on the main disk and the backup disk.
As for fire-proofing my data: I store a disk at an off-site location (parents' home), and I regularly swap my main disk with the backup disk.